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Sample records for energetic supernova sn

  1. Diversity of gamma-ray burst energetics vs. supernova homogeneity: SN 2013cq associated with GRB 130427A

    NASA Astrophysics Data System (ADS)

    Melandri, A.; Pian, E.; D'Elia, V.; D'Avanzo, P.; Della Valle, M.; Mazzali, P. A.; Tagliaferri, G.; Cano, Z.; Levan, A. J.; Møoller, P.; Amati, L.; Bernardini, M. G.; Bersier, D.; Bufano, F.; Campana, S.; Castro-Tirado, A. J.; Covino, S.; Ghirlanda, G.; Hurley, K.; Malesani, D.; Masetti, N.; Palazzi, E.; Piranomonte, S.; Rossi, A.; Salvaterra, R.; Starling, R. L. C.; Tanaka, M.; Tanvir, N. R.; Vergani, S. D.

    2014-07-01

    Aims: Long-duration gamma-ray bursts (GRBs) have been found to be associated with broad-lined type-Ic supernovae (SNe), but only a handful of cases have been studied in detail. Prompted by the discovery of the exceptionally bright, nearby GRB 130427A (redshift z = 0.3399), we aim at characterising the properties of its associated SN 2013cq. This is the first opportunity to test the progenitors of high-luminosity GRBs directly. Methods: We monitored the field of the Swift long-duration GRB 130427A using the 3.6 m TNG and the 8.2 m VLT during the time interval between 3.6 and 51.6 days after the burst. Photometric and spectroscopic observations revealed the presence of the type Ic SN 2013cq. Results: Spectroscopic analysis suggests that SN 2013cq resembles two previous GRB-SNe, SN 1998bw and SN 2010bh, associated with GRB 980425 and X-ray flash (XRF) 100316D, respectively. The bolometric light curve of SN 2013cq, which is significantly affected by the host galaxy contribution, is systematically more luminous than that of SN 2010bh (~2 mag at peak), but is consistent with SN 1998bw. The comparison with the light curve model of another GRB-connected SN 2003dh indicates that SN 2013cq is consistent with the model when brightened by 20%. This suggests a synthesised radioactive 56Ni mass of ~0.4M⊙. GRB 130427A/SN 2013cq is the first case of low-z GRB-SN connection where the GRB energetics are extreme (Eγ,iso ~ 1054 erg). We show that the maximum luminosities attained by SNe associated with GRBs span a very narrow range, but those associated with XRFs are significantly less luminous. On the other hand the isotropic energies of the accompanying GRBs span 6 orders of magnitude (1048 erg SN energy budget. Based on observations made with the VLT, operated on the mountain of Cerro Paranal in Chile under programme 091.D-0291

  2. Toward connecting core-collapse supernova theory with observations. I. Shock revival in a 15 M {sub ☉} blue supergiant progenitor with SN 1987A energetics

    SciTech Connect

    Handy, Timothy; Plewa, Tomasz; Odrzywołek, Andrzej

    2014-03-10

    We study the evolution of the collapsing core of a 15 M {sub ☉} blue supergiant supernova progenitor from the core bounce until 1.5 s later. We present a sample of hydrodynamic models parameterized to match the explosion energetics of SN 1987A. We find the spatial model dimensionality to be an important contributing factor in the explosion process. Compared to two-dimensional (2D) simulations, our three-dimensional (3D) models require lower neutrino luminosities to produce equally energetic explosions. We estimate that the convective engine in our models is 4% more efficient in 3D than in 2D. We propose that the greater efficiency of the convective engine found in 3D simulations might be due to the larger surface-to-volume ratio of convective plumes, which aids in distributing energy deposited by neutrinos. We do not find evidence of the standing accretion shock instability or turbulence being a key factor in powering the explosion in our models. Instead, the analysis of the energy transport in the post-shock region reveals characteristics of penetrative convection. The explosion energy decreases dramatically once the resolution is inadequate to capture the morphology of convection on large scales. This shows that the role of dimensionality is secondary to correctly accounting for the basic physics of the explosion. We also analyze information provided by particle tracers embedded in the flow and find that the unbound material has relatively long residency times in 2D models, while in 3D a significant fraction of the explosion energy is carried by particles with relatively short residency times.

  3. Toward Connecting Core-Collapse Supernova Theory with Observations: Nucleosynthetic Yields and Distribution of Elements in a 15 M⊙ Blue Supergiant Progenitor with SN 1987A Energetics

    NASA Astrophysics Data System (ADS)

    Plewa, Tomasz; Handy, Timothy; Odrzywolek, Andrzej

    2014-03-01

    We compute and discuss the process of nucleosynthesis in a series of core-collapse explosion models of a 15 solar mass, blue supergiant progenitor. We obtain nucleosynthetic yields and study the evolution of the chemical element distribution from the moment of core bounce until young supernova remnant phase. Our models show how the process of energy deposition due to radioactive decay modifies the dynamics and the core ejecta structure on small and intermediate scales. The results are compared against observations of young supernova remnants including Cas A and the recent data obtained for SN 1987A. The work has been supported by the NSF grant AST-1109113 and DOE grant DE-FG52-09NA29548. This research used resources of the National Energy Research Scientific Computing Center, which is supported by the U.S. DoE under Contract No. DE-AC02-05CH11231.

  4. SN 1054: A pulsar-powered supernova?

    NASA Astrophysics Data System (ADS)

    Li, Shao-Ze; Yu, Yun-Wei; Huang, Yan

    2015-11-01

    The famous ancient supernova SN 1054 could have been too bright to be explained in the “standard” radioactive-powered supernova scenario. As an alternative attempt, we demonstrate that the spin-down of the newly born Crab pulsar could provide a sufficient energy supply to make SN 1054 visible at daytime for 23 days and at night for 653 days, where a one-zone semi-analytical model is employed. Our results indicate that SN 1054 could be a “normal” cousin of magnetar-powered superluminous supernovae. Therefore, SN 1054-like supernovae could be a probe to uncover the properties of newly born neutron stars, which provide initial conditions for studies on neutron star evolutions.

  5. Quark nova imprint in the extreme supernova explosion SN 2006gy

    NASA Astrophysics Data System (ADS)

    Ouyed, R.; Kostka, M.; Koning, N.; Leahy, D. A.; Steffen, W.

    2012-06-01

    The extremely luminous supernova 2006gy (SN 2006gy) is among the most energetic ever observed. The peak brightness was 100 times that of a typical supernova and it spent an unheard of 250 d at magnitude -19 or brighter. Efforts to describe SN 2006gy have pushed the boundaries of current supernova theory. In this work we aspire to simultaneously reproduce the photometric and spectroscopic observations of SN 2006gy using a quark nova (QN) model. This analysis considers the supernova explosion of a massive star followed days later by the QN detonation of a neutron star. We lay out a detailed model of the interaction between the supernova envelope and the QN ejecta paying special attention to a mixing region which forms at the inner edge of the supernova envelope. This model is then fitted to photometric and spectroscopic observations of SN 2006gy. This QN model naturally describes several features of SN 2006gy including the late-stage light-curve plateau, the broad Hα line and the peculiar blue Hα absorption. We find that a progenitor mass between 20 and 40 M⊙ provides ample energy to power SN 2006gy in the context of a QN.

  6. Du Pont Classifications of 2 ASAS-SN Supernovae

    NASA Astrophysics Data System (ADS)

    Shappee, Benjamin J.; Prieto, J. L.; Rich, J.; Madore, B.; Poetrodjojo, Henry; D'Agostino, Joshua

    2016-09-01

    We report optical spectroscopy (range 370-910 nm) of two supernovae discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN; Shappee et al. 2014, ApJ, 788, 48) using the du Pont 2.5-m telescope (+ WFCCD) at Las Campanas Observatory on Aug. 30 and Sep. 1 2016 UT. We performed a cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J.

  7. Du Pont Classifications of 4 ASAS-SN Supernovae

    NASA Astrophysics Data System (ADS)

    Morrell, N.; Shappee, Benjamin J.

    2016-08-01

    We report optical spectroscopy (range 370-910 nm) of four supernovae discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN; Shappee et al. 2014, ApJ, 788, 48) using the du Pont 2.5-m telescope (+ WFCCD) at Las Campanas Observatory on July 31 and Aug. 01 2016 UT. We performed a cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J.

  8. SN 2010as and Transitional Ib/c Supernovae

    NASA Astrophysics Data System (ADS)

    Folatelli, Gastón

    2014-01-01

    We present intensive photometric and spectroscopic observations of SN 2010as carried out by the Millennium Center for Supernova Studies (MCSS) and the Carnegie Supernova Project (CSP). The SN belongs to the transitional type Ibc (SN Ibc) that is characterized by the slow appearance of weak helium lines with low expansion velocities. We find a wide variety of photometric properties among otherwise spectroscopically similar SN Ibc. A hydrodynamical model is used to provide physical properties of SN 2010as in comparison with the bolometric light curve and expansion velocity.

  9. ASAS-SN Discovery of Two Probable Supernovae

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Rivera, D. Godoy; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Kiyota, S.; Koff, R. A.; Krannich, G.; Masi, G.; Nicholls, B.; Nicolas, J.

    2015-10-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered two transient sources, most likely supernovae, in the galaxies 2MASX J00011837-3321048 and ESO 296-G027.

  10. SN 1987A: The Supernova of the Century

    NASA Technical Reports Server (NTRS)

    Sonneborne, George

    2012-01-01

    Supernova 1987 A in the Large Magellanic Cloud is one of the most intensively studied objects in the universe and a Rosetta Stone for understanding the explosions of massive stars. Approaching its 25th anniversary, SN 1987 A is a very young supernova remnant, a phase previously unobserved in any other supernova. The supernova of the 20th Century is now the supernova remnant of the 21st Century. In this talk I will discuss recent observations from the far-ultraviolet to the far-infrared with HST, the VLT, Spitzer, and the Herschel Space Observatory. These data reveal new insights into the composition, geometry, and heating of the explosion debris, the shock interaction with circumstellar material, and dust in the SN 1987 A system.

  11. Spectrum synthesis of the Type Ia supernovae SN 1992A and SN 1981B

    NASA Technical Reports Server (NTRS)

    Nugent, Peter; Baron, E.; Hauschildt, Peter H.; Branch, David

    1995-01-01

    We present non-local thermodynamic equilibrium (non-LTE) synthetic spectra for the Type Ia supernovae SN 1992A and SN 1981B, near maximum light. At this epoch both supernovae were observed from the UV through the optical. This wide spectral coverage is essential for determining the density structure of a SN Ia. Our fits are in good agreement with observation and provide some insight as to the differences between these supernovae. We also discuss the application of the expanding photosphere method to SNe Ia which gives a distance that is independent of those based on the decay of Ni-56 and Cepheid variable stars.

  12. Energetic Supernovae of Very Massive Primordial Stars

    NASA Astrophysics Data System (ADS)

    Chen, Ke-Jung; Woosley, Stan

    2015-08-01

    Current models of the formation of the first stars in the universe suggest that these stars were very massive, having a typical mass scale of hundreds of solar masses. Some of them would die as pair instability supernovae (PSNe) which might be the biggest explosions of the universe. We present the results from multidimensional numerical studies of PSNe with a new radiation-hydrodynamics code, CASTRO and with realistic nuclear reaction networks. We simulate the fluid instabilities that occur in multiple spatial dimensions and discuss how the resulting mixing affects the explosion, mixing, and nucleosynthesis of these supernovae. Our simulations provide useful predictions for the observational signatures of PSNe, which might soon be examined by the James Webb Space Telescope.

  13. Spectroscopic classification of supernova SN 2016fqr with the Nordic Optical Telescope

    NASA Astrophysics Data System (ADS)

    Terreran, G.; Elias-Rosa, N.; Mattila, S.; Lundqvist, P.; Stritzinger, M.; Benetti, S.; Cappellaro, E.; Blagorodnova, N.; Davis, S.; Dong, S.; Fraser, M.; Gall, C.; Harmanen, J.; Harrison, D.; Hodgkin, S.; Hsiao, E. Y.; Jonker, P.; Kangas, T.; Kankare, E.; Kuncarayakti, H.; Kostrzewa-Rutkowska, Z.; Nielsen, M.; Ochner, P.; Pastorello, A.; Prieto, J. L.; Reynolds, T.; Romero-Canizales, C.; Stanek, K.; Taddia, F.; Tartaglia, L.; Tomasella, L.; Wyrzykowski, L.

    2016-09-01

    The NOT Unbiased Transient Survey (NUTS; ATel #8992) report the spectroscopic classification of supernova SN 2016fqr in NGC 1122. The supernova was discovered by the Lick Observatory Supernova Search (LOSS).

  14. SN 1993J: A Type IIb supernova

    NASA Technical Reports Server (NTRS)

    Woosley, S. E.; Eastman, Ronald G. (Editor); Weaver, Thomas A; Pinto, Philip A.

    1994-01-01

    The evolution of the bright Type II supernova discovered last year in M81, SN 1993J, is consistent with that expected for the explosion of a star which on the main sequence had a mass of 13-16 Solar Mass but which, owing to mass exchange with a binary companion (a intially approximately 3-5 AU, depending upon the actual presupernova radius and the masses of the two stars) lost almost all of its hydrogen-rich envelope during late helium burning. At the time of explosion, the helium core mass was 4.0 +/- 0.5 Solar Mass and the hydrogen envelope, 0.20 +/- 0.05 Solar Mass. The envelope was helium and nitrogen-rich (carbon-deficient) and the radius of the star, 4 +/- 1 x 10(exp 13) cm. The luminosity of the presupernova star was 3 + 1 x 10(exp 38) ergs/s, with the companion star contributing an additional approximately 10(exp 38) ergs/s. The star may have been a pulsating variable at the time of the explosion. For an explosion energy near 10(exp 51) ergs (KE at infinity) and an assumed distance of 3.3 Mpc, a mass of Ni-56 in the range 0.07 +/- 0.01 Solar Mass was produced and ejected. This presciption gives a light curve which compares favorably with the bolomatric observations. Color photometry is more restrictive and requires a model in which the hydrogen-envelope mass is low and the mixing of hydrogen inward has been small, but in which appreciable Ni-56 has been mixed outward into the helium and heavy-element core. It is possible to obtain good agreement with B and V light curves during the first 50 days, but later photometry, especially in bands other than B and V, will require a non-local thermo-dynamic equilibrium (LTE) spectral calculation for comparison. Based upon our model, we predict a flux of approximately 10(exp -5)(3.3 Mpc/D)(exp 2) photons/sq cm/s in the 847 keV line of CO-56 at peak during 1993 August. It may be easier to detect the Computonized continuum which peaks at a few times 10(exp -4) photons /s/sq cm/MeV at 40 keV a few months after the

  15. A neutron-star-driven X-ray flash associated with supernova SN 2006aj.

    PubMed

    Mazzali, Paolo A; Deng, Jinsong; Nomoto, Ken'ichi; Sauer, Daniel N; Pian, Elena; Tominaga, Nozomu; Tanaka, Masaomi; Maeda, Keiichi; Filippenko, Alexei V

    2006-08-31

    Supernovae connected with long-duration gamma-ray bursts (GRBs) are hyper-energetic explosions resulting from the collapse of very massive stars ( approximately 40 M\\circ, where M\\circ is the mass of the Sun) stripped of their outer hydrogen and helium envelopes. A very massive progenitor, collapsing to a black hole, was thought to be a requirement for the launch of a GRB. Here we report the results of modelling the spectra and light curve of SN 2006aj (ref. 9), which demonstrate that the supernova had a much smaller explosion energy and ejected much less mass than the other GRB-supernovae, suggesting that it was produced by a star whose initial mass was only approximately 20 M\\circ. A star of this mass is expected to form a neutron star rather than a black hole when its core collapses. The smaller explosion energy of SN 2006aj is matched by the weakness and softness of GRB 060218 (an X-ray flash), and the weakness of the radio flux of the supernova. Our results indicate that the supernova-GRB connection extends to a much broader range of stellar masses than previously thought, possibly involving different physical mechanisms: a 'collapsar' (ref. 8) for the more massive stars collapsing to a black hole, and magnetic activity of the nascent neutron star for the less massive stars. PMID:16943833

  16. The Supernova Spectropolarimetry Project: Evolution of Asymmetries in the Very Luminous Type Ib SN 2012au

    NASA Astrophysics Data System (ADS)

    Hoffman, Jennifer L.; Smith, N.; Bilinski, C.; Dessart, L.; Huk, L. N.; Leonard, D. C.; Milne, P.; Smith, P. S.; Williams, G.

    2014-01-01

    The Supernova Spectropolarimetry Project is a recently formed collaboration between observers and theorists that focuses on decoding the complex, time-dependent spectropolarimetric behavior of supernovae (SNe) of all types. Using the CCD Imaging/Spectropolarimeter (SPOL) at the 61" Kuiper, the 90" Bok, and the 6.5-m MMT telescopes, we obtain multi-epoch observations of each target, aiming to construct the most comprehensive survey to date of supernovae in polarized light. In this poster we present the results of 6 epochs of spectropolarimetric observations of the Type Ib SN 2012au spanning the first 315 days of its evolution. This supernova was a very energetic, luminous, and slow-evolving event that may represent an intermediate case between normal core-collapse SNe and the enigmatic superluminous SNe (SLSNe). Strong, time-variable line polarization signatures, particularly in the He I λ5876 line, support previous hypotheses of an asymmetric explosion and allow us to trace detailed structures within the supernova ejecta as they change over time. We compare the spectropolarimetric evolution of SN 2012au with that of other objects in our data set and discuss its connections with other SNe Ib/c and SLSNe.

  17. Supernova mechanisms: Before and after SN1987a

    SciTech Connect

    Kahana, S.H.

    1987-01-01

    The impact of SN1987a on theoretical studies of the specific mechanism generating Type II supernovae is examined. The explosion energy extracted from analysis of the light curve for SN 1987a is on the edge of distinguishing between a prompt explosion from a hydrodynamic shock and a delayed, neutrino-induced, explosion. The detection of neutrinos from 1987a is also reanalyzed. 30 refs., 2 tabs.

  18. The Likely Fermi Detection of the Supernova Remnant SN 1006

    NASA Astrophysics Data System (ADS)

    Xing, Yi; Wang, Zhongxiang; Zhang, Xiao; Chen, Yang

    2016-05-01

    We report the likely detection of γ-ray emission from the northeast shell region of the historical supernova remnant (SNR) SN 1006. Having analyzed seven years of Fermi Large Area Telescope Pass 8 data for the region of SN 1006, we found a GeV gamma-ray source detected with ∼ 4σ significance. Both the position and spectrum of the source match those of HESS J1504‑418, respectively, which is TeV emission from SN 1006. Considering the source as the GeV γ-ray counterpart to SN 1006, the broadband spectral energy distribution is found to be approximately consistent with the leptonic scenario that has been proposed for the TeV emission from the SNR. Our result has likely confirmed the previous study of the SNRs with TeV shell-like morphology: SN 1006 is one of them sharing very similar peak luminosity and spectral shape.

  19. On type IIn/Ia-CSM supernovae as exemplified by SN 2012ca★

    NASA Astrophysics Data System (ADS)

    Inserra, C.; Fraser, M.; Smartt, S. J.; Benetti, S.; Chen, T.-W.; Childress, M.; Gal-Yam, A.; Howell, D. A.; Kangas, T.; Pignata, G.; Polshaw, J.; Sullivan, M.; Smith, K. W.; Valenti, S.; Young, D. R.; Parker, S.; Seccull, T.; McCrum, M.

    2016-04-01

    We present the complete set of ultra-violet, optical and near-infrared photometry and spectroscopy for SN 2012ca, covering the period from 6 days prior to maximum light, until 531 days after maximum. The spectroscopic time series for SN 2012ca is essentially unchanged over 1.5 years, and appear to be dominated at all epochs by signatures of interaction with a dense circumstellar medium rather than the underlying supernova (SN). SN 2012ca is a member of the set of type of the ambiguous IIn/Ia-CSM SNe, the nature of which have been debated extensively in the literature. The two leading scenarios are either a type Ia SN exploding within a dense CSM from a non-degenerate, evolved companion, or a core-collapse SN from a massive star. While some members of the population have been unequivocally associated with type Ia SNe, in other cases the association is less certain. While it is possible that SN 2012ca does arise from a thermonuclear SN, this would require a relatively high (between 20 and 70 per cent) efficiency in converting kinetic energy to optical luminosity, and a massive (˜2.3 - 2.6 M⊙) circumstellar medium. On the basis of energetics, and the results of simple modelling, we suggest that SN 2012ca is more likely associated with a core-collapse SN. This would imply that the observed set of similar SNe to SN 2012ca is in fact originated by two populations, and while these are drawn from physically distinct channels, they can have observationally similar properties.

  20. On Type IIn/Ia-CSM supernovae as exemplified by SN 2012ca*

    NASA Astrophysics Data System (ADS)

    Inserra, C.; Fraser, M.; Smartt, S. J.; Benetti, S.; Chen, T.-W.; Childress, M.; Gal-Yam, A.; Howell, D. A.; Kangas, T.; Pignata, G.; Polshaw, J.; Sullivan, M.; Smith, K. W.; Valenti, S.; Young, D. R.; Parker, S.; Seccull, T.; McCrum, M.

    2016-07-01

    We present the complete set of ultra-violet, optical and near-infrared photometry and spectroscopy for SN 2012ca, covering the period from 6 d prior to maximum light, until 531 d after maximum. The spectroscopic time series for SN 2012ca is essentially unchanged over 1.5 yr, and appear to be dominated at all epochs by signatures of interaction with a dense circumstellar medium (CSM) rather than the underlying supernova (SN). SN 2012ca is a member of the set of type of the ambiguous IIn/Ia-CSM SNe, the nature of which have been debated extensively in the literature. The two leading scenarios are either a Type Ia SN exploding within a dense CSM from a non-degenerate, evolved companion, or a core-collapse SN from a massive star. While some members of the population have been unequivocally associated with Type Ia SNe, in other cases the association is less certain. While it is possible that SN 2012ca does arise from a thermonuclear SN, this would require a relatively high (between 20 and 70 per cent) efficiency in converting kinetic energy to optical luminosity, and a massive (˜2.3-2.6 M⊙) circumstellar medium. On the basis of energetics, and the results of simple modelling, we suggest that SN 2012ca is more likely associated with a core-collapse SN. This would imply that the observed set of similar SNe to SN 2012ca is in fact originated by two populations, and while these are drawn from physically distinct channels, they can have observationally similar properties.

  1. SN 2012au: A GOLDEN LINK BETWEEN SUPERLUMINOUS SUPERNOVAE AND THEIR LOWER-LUMINOSITY COUNTERPARTS

    SciTech Connect

    Milisavljevic, Dan; Soderberg, Alicia M.; Margutti, Raffaella; Drout, Maria R.; Marion, G. Howie; Sanders, Nathan E.; Lunnan, Ragnhild; Chornock, Ryan; Berger, Edo; Foley, Ryan J.; Challis, Pete; Kirshner, Robert P.; Dittmann, Jason; Bieryla, Allyson; Kamble, Atish; Chakraborti, Sayan; Hsiao, Eric Y.; Fesen, Robert A.; Parrent, Jerod T.; Levesque, Emily M.; and others

    2013-06-20

    We present optical and near-infrared observations of SN 2012au, a slow-evolving supernova (SN) with properties that suggest a link between subsets of energetic and H-poor SNe and superluminous SNe. SN 2012au exhibited conspicuous Type-Ib-like He I lines and other absorption features at velocities reaching Almost-Equal-To 2 Multiplication-Sign 10{sup 4} km s{sup -1} in its early spectra, and a broad light curve that peaked at M{sub B} = -18.1 mag. Models of these data indicate a large explosion kinetic energy of {approx}10{sup 52} erg and {sup 56}Ni mass ejection of M{sub Ni} Almost-Equal-To 0.3 M{sub Sun} on par with SN 1998bw. SN 2012au's spectra almost one year after explosion show a blend of persistent Fe II P-Cyg absorptions and nebular emissions originating from two distinct velocity regions. These late-time emissions include strong [Fe II], [Ca II], [O I], Mg I], and Na I lines at velocities {approx}> 4500 km s{sup -1}, as well as O I and Mg I lines at noticeably smaller velocities {approx}< 2000 km s{sup -1}. Many of the late-time properties of SN 2012au are similar to the slow-evolving hypernovae SN 1997dq and SN 1997ef, and the superluminous SN 2007bi. Our observations suggest that a single explosion mechanism may unify all of these events that span -21 {approx}< M{sub B} {approx}< -17 mag. The aspherical and possibly jetted explosion was most likely initiated by the core collapse of a massive progenitor star and created substantial high-density, low-velocity Ni-rich material.

  2. SN 2012au: A Golden Link between Superluminous Supernovae and Their Lower-luminosity Counterparts

    NASA Astrophysics Data System (ADS)

    Milisavljevic, Dan; Soderberg, Alicia M.; Margutti, Raffaella; Drout, Maria R.; Howie Marion, G.; Sanders, Nathan E.; Hsiao, Eric Y.; Lunnan, Ragnhild; Chornock, Ryan; Fesen, Robert A.; Parrent, Jerod T.; Levesque, Emily M.; Berger, Edo; Foley, Ryan J.; Challis, Pete; Kirshner, Robert P.; Dittmann, Jason; Bieryla, Allyson; Kamble, Atish; Chakraborti, Sayan; De Rosa, Gisella; Fausnaugh, Michael; Hainline, Kevin N.; Chen, Chien-Ting; Hickox, Ryan C.; Morrell, Nidia; Phillips, Mark M.; Stritzinger, Maximilian

    2013-06-01

    We present optical and near-infrared observations of SN 2012au, a slow-evolving supernova (SN) with properties that suggest a link between subsets of energetic and H-poor SNe and superluminous SNe. SN 2012au exhibited conspicuous Type-Ib-like He I lines and other absorption features at velocities reaching ≈2 × 104 km s-1 in its early spectra, and a broad light curve that peaked at MB = -18.1 mag. Models of these data indicate a large explosion kinetic energy of ~1052 erg and 56Ni mass ejection of M Ni ≈ 0.3 M ⊙ on par with SN 1998bw. SN 2012au's spectra almost one year after explosion show a blend of persistent Fe II P-Cyg absorptions and nebular emissions originating from two distinct velocity regions. These late-time emissions include strong [Fe II], [Ca II], [O I], Mg I], and Na I lines at velocities >~ 4500 km s-1, as well as O I and Mg I lines at noticeably smaller velocities <~ 2000 km s-1. Many of the late-time properties of SN 2012au are similar to the slow-evolving hypernovae SN 1997dq and SN 1997ef, and the superluminous SN 2007bi. Our observations suggest that a single explosion mechanism may unify all of these events that span -21 <~ MB <~ -17 mag. The aspherical and possibly jetted explosion was most likely initiated by the core collapse of a massive progenitor star and created substantial high-density, low-velocity Ni-rich material.

  3. Radio evolution of supernova SN 2008iz in M 82

    NASA Astrophysics Data System (ADS)

    Kimani, N.; Sendlinger, K.; Brunthaler, A.; Menten, K. M.; Martí-Vidal, I.; Henkel, C.; Falcke, H.; Muxlow, T. W. B.; Beswick, R. J.; Bower, G. C.

    2016-08-01

    We report on multi-frequency Very Large Array (VLA) and Very Long Baseline Interferometry (VLBI) radio observations for a monitoring campaign of supernova SN 2008iz in the nearby irregular galaxy M 82. We fit two models to the data, a simple time power-law, S ∝ tβ, and a simplified Weiler model, yielding decline indices of β = -1.22 ± 0.07 (days 100-1500) and -1.41 ± 0.02 (days 76-2167), respectively. The late-time radio light-curve evolution shows flux-density flares at ~970 and ~1400 days that are a factor of ~2 and ~4 higher than the expected flux, respectively. The later flare, except for being brighter, does not show signs of decline at least from results examined so far (2014 January 23; day 2167). We derive the spectral index, α, S ∝ να for frequencies 1.4 to 43 GHz for SN 2008iz during the period from ~430 to 2167 days after the supernova explosion. The value of α shows no signs of evolution and remains steep ≈-1 throughout the period, unlike that of SN 1993J, which started flattening at ~day 970. From the 4.8 and 8.4 GHz VLBI images, the supernova expansion is seen to start with a shell-like structure that becomes increasingly more asymmetric, then breaks up in the later epochs, with bright structures dominating the southern part of the ring. This structural evolution differs significantly from SN 1993J, which remains circularly symmetric over 4000 days after the explosion. The VLBI 4.8 and 8.4 GHz images are used to derive a deceleration index, m, for SN 2008iz, of 0.86 ± 0.02, and the average expansion velocity between days 73 and 1400 as (12.1 ± 0.2) × 103 km s-1. From the energy equipartition between magnetic field and particles, we estimate the minimum total energy in relativistic particles and the magnetic fields during the supernova expansion and also find the magnetic field amplification factor for SN 2008iz to be in the range of 55-400. The VLBI images (FITS files) are only available at the CDS via anonymous ftp to http

  4. SN 2004aw: confirming diversity of Type Ic supernovae

    NASA Astrophysics Data System (ADS)

    Taubenberger, S.; Pastorello, A.; Mazzali, P. A.; Valenti, S.; Pignata, G.; Sauer, D. N.; Arbey, A.; Bärnbantner, O.; Benetti, S.; Della Valle, A.; Deng, J.; Elias-Rosa, N.; Filippenko, A. V.; Foley, R. J.; Goobar, A.; Kotak, R.; Li, W.; Meikle, P.; Mendez, J.; Patat, F.; Pian, E.; Ries, C.; Ruiz-Lapuente, P.; Salvo, M.; Stanishev, V.; Turatto, M.; Hillebrandt, W.

    2006-09-01

    Optical and near-infrared (near-IR) observations of the Type Ic supernova (SN Ic) 2004aw are presented, obtained from -3 to +413 d with respect to the B-band maximum. The photometric evolution is characterized by a comparatively slow post-maximum decline of the light curves. The peaks in redder bands are significantly delayed relative to the bluer bands, the I-band maximum occurring 8.4 d later than that in B. With an absolute peak magnitude of -18.02 in the V band the SN can be considered fairly bright, but not exceptional. This also holds for the U through I bolometric light curve, where SN 2004aw has a position intermediate between SNe 2002ap and 1998bw. Spectroscopically SN 2004aw provides a link between a normal SN Ic like SN 1994I and the group of broad-lined SNe Ic. The spectral evolution is rather slow, with a spectrum at day +64 being still predominantly photospheric. The shape of the nebular [OI] λλ6300, 6364 line indicates a highly aspherical explosion. Helium cannot be unambiguously identified in the spectra, even in the near-IR. Using an analytical description of the light-curve peak we find that the total mass of the ejecta in SN 2004aw is 3.5-8.0Msolar, significantly larger than that in SN 1994I, although not as large as in SN 1998bw. The same model suggests that about 0.3Msolar of 56Ni has been synthesized in the explosion. No connection to a GRB can be firmly established. Based on observations at ESO-Paranal, Prog. 074.D-0161(A). E-mail: tauben@mpa-garching.mpg.de

  5. Free at Last: AN Energetic Pulsar Escapes its Supernova Remnant

    NASA Astrophysics Data System (ADS)

    Camilo, Fernando

    2002-09-01

    PSR J1016-5857 is a young and energetic pulsar located just outside the supernova remnant (SNR) G284.3-1.8. The morphology of the system argues that the pulsar has a high space velocity, and has caught up with and now overtaken its associated SNR. We have identified an EINSTEIN source, which in the above hypothesis is likely to be a cometary nebula powered by the pulsar. We here propose a short CHANDRA observation of this X-ray source to determine whether it is indeed associated with the pulsar. With the resulting morphological data, we can confirm or refute the pulsar/SNR association, and can probe the pulsar's spin history and interaction with its environment.

  6. XRF 100316D/SN 2010bh AND THE NATURE OF GAMMA-RAY BURST SUPERNOVAE

    SciTech Connect

    Cano, Z.; Bersier, D.; Guidorzi, C.; Kobayashi, S.; Melandri, A.; Mundell, C. G.; Levan, A. J.; Tanvir, N. R.; Wiersema, K.; D'Avanzo, P.; Margutti, R.; Fruchter, A. S.; Garnavich, P.; Gomboc, A.; Kopac, D.; Gorosabel, J.; Kasen, D.; Mazzali, P. A.; Nugent, P. E.; Pian, E.

    2011-10-10

    We present ground-based and Hubble Space Telescope optical and infrared observations of Swift XRF 100316D/SN 2010bh. It is seen that the optical light curves of SN 2010bh evolve at a faster rate than the archetype gamma-ray burst supernova (GRB-SN) 1998bw, but at a similar rate to SN 2006aj, an SN that was spectroscopically linked with XRF 060218, and at a similar rate to the non-GRB associated Type Ic SN 1994I. We estimate the rest-frame extinction of this event from our optical data to be E(B - V) = 0.18 {+-} 0.08 mag. We find the V-band absolute magnitude of SN 2010bh to be M{sub V} = -18.62 {+-} 0.08, which is the faintest peak V-band magnitude observed to date for spectroscopically confirmed GRB-SNe. When we investigate the origin of the flux at t - t{sub 0} = 0.598 days, it is shown that the light is not synchrotron in origin, but is likely coming from the SN shock breakout. We then use our optical and infrared data to create a quasi-bolometric light curve of SN 2010bh, which we model with a simple analytical formula. The results of our modeling imply that SN 2010bh synthesized a nickel mass of M{sub Ni} {approx} 0.1 M{sub sun}, ejected M{sub ej} {approx} 2.2 M{sub sun}, and has an explosion energy of E{sub k} {approx} 1.4 x 10{sup 52} erg. Thus, while SN 2010bh is an energetic explosion, the amount of nickel created during the explosion is much less than that of SN 1998bw and only marginally more than SN 1994I. Finally, for a sample of 22 GRB-SNe we check for a correlation between the stretch factors and luminosity factors in the R band and conclude that no statistically significant correlation exists.

  7. The magnification of SN 1997ff, the farthest known supernova

    SciTech Connect

    Benitez, Narciso; Riess, Adam; Nugent, Peter; Dickinson, Mark; Chornock, Ryan; Filippenko, Alexei V.

    2002-09-03

    With a redshift of z {approx} 1.7, SN 1997ff is the most distant type Ia supernova discovered so far. This SN is close to several bright, z = 0.6-0.9 galaxies, and we consider the effects of lensing by those objects on the magnitude of SN 1997ff. We estimate their velocity dispersions using the Tully-Fisher and Faber-Jackson relations corrected for evolution effects, and calculate, applying the multiple-plane lensing formalism, that SN 1997ff is magnified by 0.34{+-}0.12 mag. Due to the spatial configuration of the foreground galaxies, the shear from individual lenses partially cancels out,and the total distortion induced on the host galaxy is considerably smaller than that produced by a single lens having the same magnification. After correction for lensing, the revised distance to SN 1997ff is m-M = 45.49 {+-} 0.34 mag, which improves the agreement with the {Omega}{sub M} = 0.35, {Omega}{Lambda} = 0.65 cosmology expected from lower-redshift SNe Ia, and is inconsistent at the {approx} 3 sigma confidence level with a uniform gray dust model or a simple evolution model.

  8. A Luminous Peculiar Type Ia Supernova SN 2011hr: More Like SN 1991T or SN 2007if?

    NASA Astrophysics Data System (ADS)

    Zhang, Ju-Jia; Wang, Xiao-Feng; Sasdelli, Michele; Zhang, Tian-Meng; Liu, Zheng-Wei; Mazzali, Paolo A.; Meng, Xiang-Cun; Maeda, Keiichi; Chen, Jun-Cheng; Huang, Fang; Zhao, Xu-Lin; Zhang, Kai-Cheng; Zhai, Qian; Pian, Elena; Wang, Bo; Chang, Liang; Yi, Wei-Min; Wang, Chuan-Jun; Wang, Xue-Li; Xin, Yu-Xin; Wang, Jian-Guo; Lun, Bao-Li; Zheng, Xiang-Ming; Zhang, Xi-Liang; Fan, Yu-Feng; Bai, Jin-Ming

    2016-02-01

    Photometric and spectroscopic observations of a slowly declining, luminous Type Ia supernova (SN Ia) SN 2011hr in the starburst galaxy NGC 2691 are presented. SN 2011hr is found to peak at {M}B\\=\\-19.84+/- 0.40 {mag}, with a postmaximum decline rate Δm15(B) = 0.92 ± 0.03 mag. From the maximum-light bolometric luminosity, L\\=\\(2.30+/- 0.90)× {10}43 {erg} {{{s}}}-1, we estimate the mass of synthesized 56Ni in SN 2011hr to be M{(}56{Ni})\\=\\1.11+/- 0.43 {M}⊙ . SN 2011hr appears more luminous than SN 1991T at around maximum light, and the absorption features from its intermediate-mass elements (IMEs) are noticeably weaker than those of the latter at similar phases. Spectral modeling suggests that SN 2011hr has IMEs of ˜0.07 {M}⊙ in the outer ejecta, which is much lower than the typical value of normal SNe Ia (i.e., 0.3-0.4 {M}⊙ ) and is also lower than the value of SN 1991T (i.e., ˜0.18 {M}⊙ ). These results indicate that SN 2011hr may arise from a Chandrasekhar-mass white dwarf progenitor that experienced a more efficient burning process in the explosion. Nevertheless, it is still possible that SN 2011hr may serve as a transitional object connecting the SN 1991T-like SNe Ia with a superluminous subclass like SN 2007if given that the latter also shows very weak IMEs at all phases.

  9. SN 2009bb: A Peculiar Broad-lined Type Ic Supernova

    NASA Astrophysics Data System (ADS)

    Pignata, Giuliano; Stritzinger, Maximilian; Soderberg, Alicia; Mazzali, Paolo; Phillips, M. M.; Morrell, Nidia; Anderson, J. P.; Boldt, Luis; Campillay, Abdo; Contreras, Carlos; Folatelli, Gastón; Förster, Francisco; González, Sergio; Hamuy, Mario; Krzeminski, Wojtek; Maza, José; Roth, Miguel; Salgado, Francisco; Levesque, Emily M.; Rest, Armin; Crain, J. Adam; Foster, Andrew C.; Haislip, Joshua B.; Ivarsen, Kevin M.; LaCluyze, Aaron P.; Nysewander, Melissa C.; Reichart, Daniel E.

    2011-02-01

    Ultraviolet, optical, and near-infrared photometry and optical spectroscopy of the broad-lined Type Ic supernova (SN) 2009bb are presented, following the flux evolution from -10 to +285 days past B-band maximum. Thanks to the very early discovery, it is possible to place tight constraints on the SN explosion epoch. The expansion velocities measured from near maximum spectra are found to be only slightly smaller than those measured from spectra of the prototype broad-lined SN 1998bw associated with GRB 980425. Fitting an analytical model to the pseudobolometric light curve of SN 2009bb suggests that 4.1 ± 1.9 M sun of material was ejected with 0.22 ± 0.06 M sun of it being 56Ni. The resulting kinetic energy is 1.8 ± 0.7 × 1052 erg. This, together with an absolute peak magnitude of M B = -18.36 ± 0.44, places SN 2009bb on the energetic and luminous end of the broad-lined Type Ic (SN Ic) sequence. Detection of helium in the early time optical spectra accompanied with strong radio emission and high metallicity of its environment makes SN 2009bb a peculiar object. Similar to the case for gamma-ray bursts (GRBs), we find that the bulk explosion parameters of SN 2009bb cannot account for the copious energy coupled to relativistic ejecta, and conclude that another energy reservoir (a central engine) is required to power the radio emission. Nevertheless, the analysis of the SN 2009bb nebular spectrum suggests that the failed GRB detection is not imputable to a large angle between the line-of-sight and the GRB beamed radiation. Therefore, if a GRB was produced during the SN 2009bb explosion, it was below the threshold of the current generation of γ-ray instruments. This paper includes data gathered with the 6.5-m Magellan Telescopes located at Las Campanas Observatory, Chile. Based on observations obtained at the Gemini Observatory, Cerro Pachon, Chile (Gemini Programs GS-2009A-Q-17 and GS-2009A-Q-43).

  10. Origin of Galactic Type-Ia supernovae: SN 1572 and SN 1006

    NASA Astrophysics Data System (ADS)

    González-Hernández, J. I.; Ruiz-Lapuente, P.; Tabernero, H. M.; Montes, D.; Canal, R.; Méndez, J.; Bedin, L. R.

    2015-05-01

    We have been searching for surviving companions of progenitors of Galactic Type-Ia supernovae, in particular SN 1572 and SN 1006. These companion stars are expected to show peculiarities: (i) to be probably more luminous than the Sun, (ii) to have high radial velocity and proper motion, (iii) to be possibly enriched in metals from the SNIa ejecta, and (iv) to be located at the distance of the SNIa remnant. We have been characterizing possible candidate stars using high-resolution spectroscopic data taken at 10m-Keck and 8.2m-VLT facilities. We have identified a very promising candidate companion (Tycho G) for SN 1572 (see Ruiz-Lapuente et al. 2004; however for a different view see Kerzendorf et al., 2012) but we have not found any candidate companion for SN 1006, suggesting that SN event occurred in 1006 could have been the result of the merging of two white dwarfs (see González-Hernández et al., 2012). Adding these results to the evidence from the other direct searches, the clear minority of cases (20% or less) seem to disfavour the single-degenerate channel or that preferentially the single-degenerate escenario would involve main-sequence companions less massive than the Sun. Therefore, it appears to be very important to continue investigating these and other Galactic Type-Ia SNe such as the Johannes Kepler SN 1604.

  11. Supernova SN 2012dn: a spectroscopic clone of SN 2006gz

    NASA Astrophysics Data System (ADS)

    Chakradhari, N. K.; Sahu, D. K.; Srivastav, S.; Anupama, G. C.

    2014-09-01

    We present optical and UV analysis of the luminous Type Ia supernova SN 2012dn covering the period from ˜-11 to +109 d with respect to the B-band maximum, which occurred on JD 245 6132.89 ± 0.19, with an apparent magnitude of mB^max = 14.38 ± 0.02. The absolute magnitudes at maximum in B and V bands are MB^max = -19.52 ± 0.15 and MV^max = -19.42 ± 0.15, respectively. SN 2012dn is marginally luminous compared to normal Type Ia supernovae. The peak bolometric luminosity of log L_bol^max = 43.27 ± 0.06 erg s-1 suggests that 0.82 ± 0.12 M⊙ of 56Ni was synthesized in the explosion. The decline rate Δm15(B)true = 0.92 ± 0.04 mag is lower than that of normal Type Ia supernovae, and similar to the luminous SN 1991T. However, the photometric and spectroscopic behaviour of SN 2012dn is different from that of SN 1991T. Early-phase light curves in R and I bands are very broad. The I-band peak has a plateau-like appearance similar to the super-Chandra SN 2009dc. Pre-maximum spectra show clear evidence of C II 6580 Å line, indicating the presence of unburned materials. The velocity evolution of C II line is peculiar. Except for the very early phase (˜-13 d), the C II line velocity is lower than the velocity estimated using the Si II line. During the pre-maximum and close to the maximum phase, to reproduce observed shape of the spectra, the synthetic spectrum code SYN++ needs significantly higher blackbody temperature than those required for normal Type Ia events. The photospheric velocity evolution and other spectral properties are similar to those of the carbon-rich SN 2006gz.

  12. Interacting supernovae and supernova impostors. SN 2007sv: the major eruption of a massive star in UGC 5979

    NASA Astrophysics Data System (ADS)

    Tartaglia, L.; Pastorello, A.; Taubenberger, S.; Cappellaro, E.; Maund, J. R.; Benetti, S.; Boles, T.; Bufano, F.; Duszanowicz, G.; Elias-Rosa, N.; Harutyunyan, A.; Hermansson, L.; Höflich, P.; Maguire, K.; Navasardyan, H.; Smartt, S. J.; Taddia, F.; Turatto, M.

    2015-02-01

    We report the results of the photometric and spectroscopic monitoring campaign of the transient SN 2007sv. The observables are similar to those of Type IIn supernovae, a well-known class of objects whose ejecta interact with pre-existing circumstellar material (CSM). The spectra show a blue continuum at early phases and prominent Balmer lines in emission; however, the absolute magnitude at the discovery of SN 2007sv (MR = -14.25 ± 0.38) indicate it to be most likely a supernova impostor. This classification is also supported by the lack of evidence in the spectra of very high velocity material as expected in supernova ejecta. In addition, we find no unequivocal evidence of broad lines of α- and/or Fe-peak elements. The comparison with the absolute light curves of other interacting objects (including Type IIn supernovae) highlights the overall similarity with the prototypical impostor SN 1997bs. This supports our claim that SN 2007sv was not a genuine supernova, and was instead a supernova impostor, most likely similar to the major eruption of a luminous blue variable.

  13. The Peculiar SN 2005hk: Do Some Type Ia Supernovae Explode As Deflagrations?

    SciTech Connect

    Phillips, M.M.; Li, W.; Frieman, J.A.; Blinnikov, S.I.; DePoy, D.; Prieto, J.L.; Milne, P.; Contreras, C.; Folatelli, Gaston; Morrell, N.; Hamuy, M.; Suntzeff, N.B.; Roth, M.; Gonzalez, S.; Krzeminski, W.; Filippenko, A.V.; Freedman, W.L.; Chornock, R.; Jha, S.; Madore, B.F.; Persson, S.E.; /Las Campanas Observ. /UC, Berkeley, Astron. Dept. /Chicago U., Astron. Astrophys. Ctr. /KICP, Chicago /Fermilab /Moscow, ITEP /Garching, Max Planck Inst. /Ohio State U., Dept. Astron. /Arizona U., Astron. Dept. - Steward Observ. /Chile U., Santiago /Texas A-M /Carnegie Inst. Observ. /KIPAC, Menlo Park /Caltech, IPAC /Notre Dame U. /South African Astron. Observ. /Cape Town U. /Washington U., Seattle, Astron. Dept. /New Mexico State U. /Chicago U., FLASH /Baltimore, Space Telescope Sci.

    2006-11-14

    We present extensive u{prime}g{prime}r{prime}i{prime} BV RIY JHK{sub s} photometry and optical spectroscopy of SN 2005hk. These data reveal that SN 2005hk was nearly identical in its observed properties to SN 2002cx, which has been called 'the most peculiar known type Ia supernova'. Both supernovae exhibited high ionization SN 1991T-like pre-maximum spectra, yet low peak luminosities like SN 1991bg. The spectra reveal that SN 2005hk, like SN 2002cx, exhibited expansion velocities that were roughly half those of typical type Ia supernovae. The R and I light curves of both supernovae were also peculiar in not displaying the secondary maximum observed for normal type Ia supernovae. Our Y JH photometry of SN 2005hk reveals the same peculiarity in the near-infrared. By combining our optical and near-infrared photometry of SN 2005hk with published ultraviolet light curves obtained with the Swift satellite, we are able to construct a bolometric light curve from {approx} 10 days before to {approx}60 days after B maximum. The shape and unusually low peak luminosity of this light curve, plus the low expansion velocities and absence of a secondary maximum at red and near-infrared wavelengths, are all in reasonable agreement with model calculations of a 3D deflagration which produces {approx} 0.25 M{sub {circle_dot}} of {sup 56}Ni.

  14. SN 2000cx and SN 2013bh: extremely rare, nearly twin Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Silverman, Jeffrey M.; Vinko, Jozsef; Kasliwal, Mansi M.; Fox, Ori D.; Cao, Yi; Johansson, Joel; Perley, Daniel A.; Tal, David; Wheeler, J. Craig; Amanullah, Rahman; Arcavi, Iair; Bloom, Joshua S.; Gal-Yam, Avishay; Goobar, Ariel; Kulkarni, Shrinivas R.; Laher, Russ; Lee, William H.; Marion, G. H.; Nugent, Peter E.; Shivvers, Isaac

    2013-12-01

    The Type Ia supernova (SN Ia) SN 2000cx was one of the most peculiar transients ever discovered, with a rise to maximum brightness typical of a SN Ia, but a slower decline and a higher photospheric temperature. 13 yr later SN 2013bh (also known as iPTF13abc), a near identical twin, was discovered and we obtained optical and near-infrared photometry and low-resolution optical spectroscopy from discovery until about 1 month past r-band maximum brightness. The spectra of both objects show iron-group elements [Co II, Ni II, Fe II, Fe III and high-velocity features (HVFs) of Ti II], intermediate-mass elements (Si II, Si III and S II) and separate normal velocity features (˜12 000 km s-1) and HVFs (˜24 000 km s-1) of Ca II. Persistent absorption from Fe III and Si III, along with the colour evolution, implies high blackbody temperatures for SNe 2013bh and 2000cx (˜12 000 K). Both objects lack narrow Na I D absorption and exploded in the outskirts of their hosts, indicating that the SN environments were relatively free of interstellar or circumstellar material and may imply that the progenitors came from a relatively old and low-metallicity stellar population. Models of SN 2000cx, seemingly applicable to SN 2013bh, imply the production of up to ˜1 M⊙ of 56Ni and (4.3-5.5) × 10-3 M⊙ of fast-moving Ca ejecta.

  15. Supernova SN 1006 in two historic Yemeni reports

    NASA Astrophysics Data System (ADS)

    Rada, W.; Neuhäuser, R.

    2015-04-01

    We present two Arabic texts of historic observations of supernova SN 1006 from Yemen as reported by al-Yamāni and Ibn al-Daybac (14th to 16th century AD). An English translation of the report by the latter was given before (Stephenson & Green 2002), but the original Arabic text was not yet published. In addition, we present for the first time the earlier report, also from Yemen, namely by al-Yamāni in its original Arabic and with our English translation. It is quite obvious that the report by Ibn al-Daybac is based on the report by al-Yamāni (or a common source), but the earlier report by al-Yamāni is more detailed and in better (Arabic) language. We discuss in detail the dating of these observations. The most striking difference to other reports about SN 1006 is the apparent early discovery in Yemen in the evening of {15th of Rajab} of the year 396h (i.e. AD 1006 April 17 ± 2 on the Julian calendar), as reported by both al-Yamāni and Ibn al-Daybac, i.e. {˜ 1.5} weeks earlier than the otherwise earliest known reports. We also briefly discuss other information from the Yemeni reports on brightness, light curve, duration of visibility, location, stationarity, and color.

  16. The peculiar case of the “double-humped" super-luminous supernova SN 2006oz

    NASA Astrophysics Data System (ADS)

    Ouyed, Rachid; Leahy, Denis

    2013-10-01

    SN 2006oz is a super-luminous supernova with a mysterious bright precursor that has resisted explanation in standard models. However, such a precursor has been predicted in the dual-shock quark nova model of super-luminous supernovae — the precursor is the supernova event while the main light curve of the super-luminous supernova is powered by the Quark-Nova (explosive transition of the neutron star to a quark star). As the supernova is fading, the Quark-Nova re-energizes the supernova ejecta, producing a “double-humped" light curve. We show that the quark nova model successfully reproduces the observed light curve of SN 2006oz.

  17. ASASSN-16bl and ASASSN-16bm: ASAS-SN Discovery of Two Probable Supernovae

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Kiyota, S.; Brown, J. S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Bock, G.; Cruz, I.; Fernandez, J. M.

    2016-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered two new transient sources, most likely supernovae, in the galaxies 2MASX J11422674-3654256 and GALEXASC J115155.68-132459.3.

  18. ASAS-SN Discovery of A Probable Supernova in ESO 297-G037

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Conseil, E.; Fernandez, J. M.; Kiyota, S.; Nicholls, B.; Nicolas, J.; Wiethoff, W.

    2015-06-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the double 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy ESO 297-G037.

  19. ASAS-SN Discovery of A Probable Supernova in SDSS J080519.59+225751.1

    NASA Astrophysics Data System (ADS)

    Nicolas, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Rivera, D. Godoy; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.; Falco, E.; Wozniak, P. R.; Pojmanski, G.; Bock, G.; Carballo, J. G.; Cruz, I.; Kiyota, S.; Marples, P.; Masi, G.

    2015-09-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy SDSS J080519.59+225751.1.

  20. ASAS-SN Discovery of A Probable Supernova in CGCG 063-098

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Goss, N.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Wozniak, P. R.; Falco, E.; Szczygiel, D.; Pojmanski, G.; Carballo, J. G.; Kiyota, S.; Koff, R. A.; Krannich, G.; Monard, L. A. G.; Nicholls, B.; Nicolas, J.; Wiethoff, W.

    2015-04-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy CGCG 063-098.

  1. ASAS-SN Discovery of A Probable Supernova in SDSS J132112.88+401556.7

    NASA Astrophysics Data System (ADS)

    Fernandez, J. M.; Masi, G.; Brown, J. S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Brimacombe, J.; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Conseil, E.; Kiyota, S.; Nicolas, J.

    2015-06-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy SDSS J132112.88+401556.7.

  2. ASAS-SN Discovery of A Probable Supernova in SDSS J152523.40+291018.8

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Fernandez, J. M.; Kiyota, S.; Masi, G.; Nicholls, B.; Nicolas, J.

    2015-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy SDSS J152523.40+291018.8.

  3. ASAS-SN Discovery of A Probable Supernova in GALEXASC J015900.57-322225.2

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Conseil, E.; Fernandez, J. M.; Kiyota, S.; Masi, G.; Nicolas, J.

    2015-06-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the double 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy GALEXASC J015900.57-322225.2.

  4. ATel 7548: ASAS-SN Discovery of A Probable Supernova in 2MFGC 08437

    NASA Astrophysics Data System (ADS)

    Nicolas, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Goss, N.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Brimacombe, J.; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Carballo, J. G.; Fernandez, J. M.; Kiyota, S.; Nicholls, B.; Wiethoff, W.

    2015-05-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy 2MFGC 08437. ...

  5. ASAS-SN Discovery of A Probable Supernova in NGC 5517

    NASA Astrophysics Data System (ADS)

    Kiyota, S.; Brimacombe, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Conseil, E.; Masi, G.; Nicholls, B.; Nicolas, J.; Polsgrove, D. E.; Della-Rose, D. J.; Novotny, S. J.; Wilber, A.; Zinn, J.; Wagner, R. M.; Neric, M.

    2015-06-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy NGC 5517.

  6. ASAS-SN Discovery of A Probable Supernova in UGC 09108 NED02

    NASA Astrophysics Data System (ADS)

    Nicolas, J.; Masi, G.; Catalano, P.; Fernandez, J. M.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Brimacombe, J.; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.

    2015-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy UGC 09108 NED02.

  7. ASAS-SN Discovery of A Probable Supernova in ESO 069-G005

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Goss, N.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Wozniak, P. R.; Falco, E.; Szczygiel, D.; Pojmanski, G.; Carballo, J. G.; Kiyota, S.; Koff, R. A.; Krannich, G.; Monard, L. A. G.; Nicholls, B.; Nicolas, J.; Wiethoff, W.

    2015-04-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the double 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy ESO 069-G005.

  8. ASAS-SN Discovery of A Probable Supernova in 2MASX J13080914+2749354

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Holoien, T. W.-S.; Bersier, D.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Dong, Subo; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Fernandez, J. M.; Kiyota, S.; Nicholls, B.; Nicolas, J.; Wiethoff, W.

    2015-05-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J13080914+2749354.

  9. ASAS-SN Discovery of A Probable Supernova in CGCG 448-007

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Wiethoff, W.; Koff, R. A.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Godoy-Rivera, D.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Kiyota, S.; Krannich, G.; Masi, G.; Nicholls, B.; Nicolas, J.

    2015-10-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy CGCG 448-007.

  10. ASAS-SN Discovery of A Possible Supernova Near 2MASXi J0909234-044327

    NASA Astrophysics Data System (ADS)

    Kiyota, S.; Brimacombe, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Goss, N.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Wozniak, P. R.; Falco, E.; Szczygiel, D.; Pojmanski, G.; Carballo, J. G.; Fernandez, J. M.; Koff, R. A.; Krannich, G.; Monard, L. A. G.; Nicholls, B.; Nicolas, J.; Wiethoff, W.

    2015-04-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the double 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, possibly a supernova, near the extended source 2MASXi J0909234-044327.

  11. ASAS-SN Discovery of A Probable Supernova in ESO 221-G012

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Carballo, J. G.; Conseil, E.; Kiyota, S.; Koff, R. A.; Masi, G.; Nicholls, B.; Nicolas, J.; Wiethoff, W.

    2015-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the double 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy ESO 221-G012.

  12. ASAS-SN Discovery of A Probable Bright Supernova in IC 4303

    NASA Astrophysics Data System (ADS)

    Kiyota, S.; Brimacombe, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Conseil, E.; Masi, G.; Nicholls, B.; Nicolas, J.; Polsgrove, D. E.; Della-Rose, D. J.; Novotny, S. J.

    2015-06-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the double 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new bright transient source, most likely a supernova, in the galaxy IC 4303.

  13. ASAS-SN Discovery of A Probable Supernova in 2MASX J15254441+5921091

    NASA Astrophysics Data System (ADS)

    Nicolas, J.; Fernandez, J. M.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Brimacombe, J.; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Kiyota, S.; Monard, L. A. G.; Nicholls, B.; Wiethoff, W.

    2015-05-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J15254441+5921091.

  14. ASAS-SN Discovery of A Probable Supernova in SDSS J100807.76+191758.2

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Koff, R. A.; Kiyota, S.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Rivera, D. Godoy; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Krannich, G.; Nicholls, B.; Nicolas, J.

    2015-10-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy SDSS J100807.76+191758.2.

  15. ASAS-SN Discovery of A Probable Supernova in 2MASX J05014660-1343503

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Fernandez, J. M.; Kiyota, S.; Koff, R. A.; Masi, G.; Monard, L. A. G.; Nicholls, B.; Nicolas, J.

    2015-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the double 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J05014660-1343503.

  16. ASAS-SN Discovery of A Probable Supernova in 2MASX J20030163-2154516

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Fernandez, J. M.; Masi, G.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Kiyota, S.; Nicholls, B.; Nicolas, J.

    2015-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J20030163-2154516.

  17. ASAS-SN Discovery of A Probable Supernova in ESO 357-G005

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Marples, P.; Kiyota, S.; Bock, G.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Rivera, D. Godoy; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Falco, E.; Wozniak, P. R.; Pojmanski, G.; Cruz, I.; Koff, R. A.; Nicolas, J.

    2015-09-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy ESO 357-G005.

  18. ASAS-SN Discovery of A Probable Supernova in 2MASX J15322270+4150586

    NASA Astrophysics Data System (ADS)

    Masi, G.; Nicolas, J.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Brimacombe, J.; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.

    2015-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J15322270+4150586.

  19. ASAS-SN Discovery of A Probable Supernova in LCRS B102206.7-024353

    NASA Astrophysics Data System (ADS)

    Kiyota, S.; Brimacombe, J.; Nicholls, B.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Goss, N.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Wozniak, P. R.; Falco, E.; Szczygiel, D.; Pojmanski, G.; Carballo, J. G.; Koff, R. A.; Krannich, G.; Monard, L. A. G.; Nicolas, J.; Wiethoff, W.

    2015-04-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the double 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy LCRS B102206.7-024353.

  20. ASAS-SN Discovery of A Probable Bright Supernova in Mrk 0576

    NASA Astrophysics Data System (ADS)

    Kiyota, S.; Brimacombe, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Conseil, E.; Fernandez, J. M.; Koff, R. A.; Masi, G.; Nicolas, J.

    2015-06-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a bright supernova, in the galaxy Mrk 0576.

  1. ASAS-SN Discovery of A Probable Supernova in NGC 2115A

    NASA Astrophysics Data System (ADS)

    Nicholls, B.; Brimacombe, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Goss, N.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Wozniak, P. R.; Falco, E.; Szczygiel, D.; Pojmanski, G.; Carballo, J. G.; Fernandez, J. M.; Kiyota, S.; Koff, R. A.; Krannich, G.; Monard, L. A. G.; Nicolas, J.; Wiethoff, W.

    2015-04-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the double 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy NGC 2115A.

  2. ASAS-SN Discovery of A Probable Bright Supernova in 2MASX J08401168-0435369

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Kiyota, S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Fernandez, J. M.; Nicholls, B.; Nicolas, J.; Wiethoff, W.

    2015-05-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the double 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J08401168-0435369.

  3. Relativistic Supernovae have Shorter-lived Central Engines or More Extended Progenitors: The Case of SN 2012ap

    NASA Astrophysics Data System (ADS)

    Margutti, R.; Milisavljevic, D.; Soderberg, A. M.; Guidorzi, C.; Morsony, B. J.; Sanders, N.; Chakraborti, S.; Ray, A.; Kamble, A.; Drout, M.; Parrent, J.; Zauderer, A.; Chomiuk, L.

    2014-12-01

    Deep, late-time X-ray observations of the relativistic, engine-driven, type Ic SN 2012ap allow us to probe the nearby environment of the explosion and reveal the unique properties of relativistic supernova explosions (SNe). We find that on a local scale of ~0.01 pc the environment was shaped directly by the evolution of the progenitor star with a pre-explosion mass-loss rate of \\dot{M} <5 × 10-6 {M⊙ yr-1}, in line with gamma-ray bursts (GRBs) and the other relativistic SN 2009bb. Like sub-energetic GRBs, SN 2012ap is characterized by a bright radio emission and evidence for mildly relativistic ejecta. However, its late-time (δt ≈ 20 days) X-ray emission is ~100 times fainter than the faintest sub-energetic GRB at the same epoch, with no evidence for late-time central engine activity. These results support theoretical proposals that link relativistic SNe like 2009bb and 2012ap with the weakest observed engine-driven explosions, where the jet barely fails to break out. Furthermore, our observations demonstrate that the difference between relativistic SNe and sub-energetic GRBs is intrinsic and not due to line-of-sight effects. This phenomenology can either be due to an intrinsically shorter-lived engine or to a more extended progenitor in relativistic SNe.

  4. THE HIGHLY ENERGETIC EXPANSION OF SN 2010bh ASSOCIATED WITH GRB 100316D

    SciTech Connect

    Bufano, Filomena; Pian, Elena; Turatto, Massimo; Sollerman, Jesper; Benetti, Stefano; Valenti, Stefano; Cappellaro, Enrico; Mazzali, Paolo A.; Pignata, Giuliano; Covino, Stefano; D'Avanzo, Paolo; Vergani, Susanna D.; Malesani, Daniele; Fynbo, Johan; Hjorth, Jens; Della Valle, Massimo; Reichart, Daniel E.; Starling, Rhaana L. C.; Wiersema, Klass; Amati, Lorenzo; and others

    2012-07-01

    We present the spectroscopic and photometric evolution of the nearby (z = 0.059) spectroscopically confirmed Type Ic supernova, SN 2010bh, associated with the soft, long-duration gamma-ray burst (X-ray flash) GRB 100316D. Intensive follow-up observations of SN 2010bh were performed at the ESO Very Large Telescope (VLT) using the X-shooter and FORS2 instruments. Thanks to the detailed temporal coverage and the extended wavelength range (3000-24800 A), we obtained an unprecedentedly rich spectral sequence among the hypernovae, making SN 2010bh one of the best studied representatives of this SN class. We find that SN 2010bh has a more rapid rise to maximum brightness (8.0 {+-} 1.0 rest-frame days) and a fainter absolute peak luminosity (L{sub bol} Almost-Equal-To 3 Multiplication-Sign 10{sup 42} erg s{sup -1}) than previously observed SN events associated with GRBs. Our estimate of the ejected {sup 56}Ni mass is 0.12 {+-} 0.02 M{sub Sun }. From the broad spectral features, we measure expansion velocities up to 47,000 km s{sup -1}, higher than those of SNe 1998bw (GRB 980425) and 2006aj (GRB 060218). Helium absorption lines He I {lambda}5876 and He I 1.083 {mu}m, blueshifted by {approx}20,000-30,000 km s{sup -1} and {approx}28,000-38,000 km s{sup -1}, respectively, may be present in the optical spectra. However, the lack of coverage of the He I 2.058 {mu}m line prevents us from confirming such identifications. The nebular spectrum, taken at {approx}186 days after the explosion, shows a broad but faint [O I] emission at 6340 A. The light curve shape and photospheric expansion velocities of SN 2010bh suggest that we witnessed a highly energetic explosion with a small ejected mass (E{sub k} Almost-Equal-To 10{sup 52} erg and M{sub ej} Almost-Equal-To 3 M{sub Sun }). The observed properties of SN 2010bh further extend the heterogeneity of the class of GRB SNe.

  5. Directed Searches for Broadband Extended Gravitational Wave Emission in Nearby Energetic Core-collapse Supernovae

    NASA Astrophysics Data System (ADS)

    van Putten, Maurice H. P. M.

    2016-03-01

    Core-collapse supernovae (CC-SNe) are factories of neutron stars and stellar-mass black holes. SNe Ib/c stand out as potentially originating in relatively compact stellar binaries and they have a branching ratio of about 1% into long gamma-ray bursts. The most energetic events probably derive from central engines harboring rapidly rotating black holes, wherein the accretion of fall-back matter down to the innermost stable circular orbit (ISCO) offers a window into broadband extended gravitational wave emission (BEGE). To search for BEGE, we introduce a butterfly filter in time-frequency space by time-sliced matched filtering. To analyze long epochs of data, we propose using coarse-grained searches followed by high-resolution searches on events of interest. We illustrate our proposed coarse-grained search on two weeks of LIGO S6 data prior to SN 2010br (z = 0.002339) using a bank of up to 64,000 templates of one-second duration covering a broad range in chirp frequencies and bandwidth. Correlating events with signal-to-noise ratios > 6 from the LIGO L1 and H1 detectors reduces the total to a few events of interest. Lacking any further properties reflecting a common excitation by broadband gravitational radiation, we disregarded these as spurious. This new pipeline may be used to systematically search for long-duration chirps in nearby CC-SNe from robotic optical transient surveys using embarrassingly parallel computing.

  6. Large and Energetic Supernova Remnant Candidates Are Jet-Inflated Bubbles

    NASA Astrophysics Data System (ADS)

    Pakull, Manfred

    Among optically selected supernova remnants in nearby galaxies a few are exceptionally large (¿ 200 pc), presumably very energetic (¿ E52 erg) and have therefore been associated with putative "hypernova" events. Here we show that the extreme cases are not due to SN explosions, but rather harbour luminous X-ray binaries (often of the ULX variety) in their centers that also emit powerful relativistic winds/jets. The jets display mechanical powers of up to some E40 erg/s that can inflate supersonically expanding, huge interstellar bubbles with diameters reaching 1 kpc. The sample includes the famous case of SS433 with its associated radio nebula W50 as well as the SNR candidate S26 in the Sculptor galaxy NGC 7793 which we recently discovered to display X-ray/optical/radio hot spots and jet-inflated lobes around a central (micro-)quasar strikingly resembling a scaled-down version of a FRII-type radio galaxy

  7. XRF 100316D/SN 2010bh: CLUE TO THE DIVERSE ORIGIN OF NEARBY SUPERNOVA-ASSOCIATED GAMMA-RAY BURSTS

    SciTech Connect

    Fan Yizhong; Zhang Bibbin; Liang Enwei; Zhang Bing; Xu Dong E-mail: zhang@physics.unlv.edu

    2011-01-01

    X-ray Flash (XRF) 100316D, a nearby super-long underluminous burst with a peak energy E{sub p} {approx} 20 keV, was detected by Swift and was found to be associated with an energetic supernova SN 2010bh. Both the spectral and the temporal behavior are rather similar to XRF 060218, except that the latter was associated with a 'less energetic' SN 2006aj and had a prominent soft thermal emission component in the spectrum. We analyze the spectral and temporal properties of this burst and interpret the prompt gamma-ray emission and the early X-ray plateau emission as synchrotron emission from a dissipating Poynting flux dominated outflow, probably powered by a magnetar with a spin period of P {approx} 10 ms and the polar cap magnetic field B{sub p} {approx} 3 x 10{sup 15} G. The energetic supernova SN 2010bh associated with this burst is, however, difficult to interpret within the slow magnetar model, and we suspect that the nascent magnetar may spin much faster with an initial rotation period {approx}1 ms. It suggests a delay between the core collapse and the emergence of the relativistic magnetar wind from the star. The diverse behaviors of low-luminosity gamma-ray bursts and their associated supernovae may be understood within a unified picture that invokes different initial powers of the central engine and different delay times between the core collapse and the emergence of the relativistic jet from the star.

  8. INTERACTING SUPERNOVAE AND SUPERNOVA IMPOSTORS: SN 2009ip, IS THIS THE END?

    SciTech Connect

    Pastorello, A.; Cappellaro, E.; Benetti, S.; Inserra, C.; Smartt, S. J.; Fraser, M.; Pignata, G.; Takats, K.; Bufano, F.; Valenti, S.; Benitez, S.; Botticella, M. T.; Brimacombe, J.; Cellier-Holzem, F.; Costado, M. T.; Cupani, G.; Curtis, I.; Elias-Rosa, N.; Ergon, M.; Fynbo, J. P. U.; and others

    2013-04-10

    We report the results of a three-year-long dedicated monitoring campaign of a restless luminous blue variable (LBV) in NGC 7259. The object, named SN 2009ip, was observed photometrically and spectroscopically in the optical and near-infrared domains. We monitored a number of erupting episodes in the past few years, and increased the density of our observations during eruptive episodes. In this paper, we present the full historical data set from 2009 to 2012 with multi-wavelength dense coverage of the two high-luminosity events between 2012 August and September. We construct bolometric light curves and measure the total luminosities of these eruptive or explosive events. We label them the 2012a event (lasting {approx}50 days) with a peak of 3 Multiplication-Sign 10{sup 41} erg s{sup -1}, and the 2012b event (14 day rise time, still ongoing) with a peak of 8 Multiplication-Sign 10{sup 42} erg s{sup -1}. The latter event reached an absolute R-band magnitude of about -18, comparable to that of a core-collapse supernova (SN). Our historical monitoring has detected high-velocity spectral features ({approx}13,000 km s{sup -1}) in 2011 September, one year before the current SN-like event. This implies that the detection of such high-velocity outflows cannot, conclusively, point to a core-collapse SN origin. We suggest that the initial peak in the 2012a event was unlikely to be due to a faint core-collapse SN. We propose that the high intrinsic luminosity of the latest peak, the variability history of SN 2009ip, and the detection of broad spectral lines indicative of high-velocity ejecta are consistent with a pulsational pair-instability event, and that the star may have survived the last outburst. The question of the survival of the LBV progenitor star and its future fate remain open issues, only to be answered with future monitoring of this historically unique explosion.

  9. Electron Cooling in a Young Radio Supernova: SN 2012aw

    NASA Astrophysics Data System (ADS)

    Yadav, Naveen; Ray, Alak; Chakraborti, Sayan; Stockdale, Christopher; Chandra, Poonam; Smith, Randall; Roy, Rupak; Bose, Subhash; Dwarkadas, Vikram; Sutaria, Firoza; Pooley, David

    2014-02-01

    We present the radio observations and modeling of an optically bright Type II-P supernova (SN), SN 2012aw which exploded in the nearby galaxy Messier 95 (M95) at a distance of 10 Mpc. The spectral index values calculated using C, X, and K bands are smaller than the expected values for the optically thin regime. During this time, the optical bolometric light curve stays in the plateau phase. We interpret the low spectral-index values to be a result of electron cooling. On the basis of comparison between the Compton cooling timescale and the synchrotron cooling timescale, we find that the inverse Compton cooling process dominates over the synchrotron cooling process. We therefore model the radio emission as synchrotron emission from a relativistic electron population with a high energy cutoff. The cutoff is determined by comparing the electron cooling timescale, t cool, and the acceleration timescale, \\tilde{t}_{acc}. We constrain the mass-loss rate in the wind (\\dot{M}\\sim 1.9\\times 10^{-6}\\ M_{\\odot }\\,yr^{-1}) and the equipartition factor between relativistic electrons and the magnetic field (\\tilde{\\alpha }=\\epsilon _e/\\epsilon _B\\sim 1.12\\times 10^2) through our modeling of radio emission. Although the time of explosion is fairly well constrained by optical observations within about two days, we explore the effect of varying the time of explosion to best fit the radio light curves. The best fit is obtained for the explosion date as 2012 March 15.3 UT.

  10. Electron cooling in a young radio supernova: SN 2012aw

    SciTech Connect

    Yadav, Naveen; Ray, Alak; Chakraborti, Sayan; Stockdale, Christopher; Chandra, Poonam; Smith, Randall; Roy, Rupak; Bose, Subhash; Dwarkadas, Vikram; Sutaria, Firoza; Pooley, David E-mail: akr@tifr.res.in

    2014-02-10

    We present the radio observations and modeling of an optically bright Type II-P supernova (SN), SN 2012aw which exploded in the nearby galaxy Messier 95 (M95) at a distance of 10 Mpc. The spectral index values calculated using C, X, and K bands are smaller than the expected values for the optically thin regime. During this time, the optical bolometric light curve stays in the plateau phase. We interpret the low spectral-index values to be a result of electron cooling. On the basis of comparison between the Compton cooling timescale and the synchrotron cooling timescale, we find that the inverse Compton cooling process dominates over the synchrotron cooling process. We therefore model the radio emission as synchrotron emission from a relativistic electron population with a high energy cutoff. The cutoff is determined by comparing the electron cooling timescale, t {sub cool}, and the acceleration timescale, t-tilde {sub acc}. We constrain the mass-loss rate in the wind ( M-dot ∼1.9×10{sup −6} M{sub ⊙} yr{sup −1}) and the equipartition factor between relativistic electrons and the magnetic field ( α-tilde =ϵ{sub e}/ϵ{sub B}∼1.12×10{sup 2}) through our modeling of radio emission. Although the time of explosion is fairly well constrained by optical observations within about two days, we explore the effect of varying the time of explosion to best fit the radio light curves. The best fit is obtained for the explosion date as 2012 March 15.3 UT.

  11. Nuclear γ ray lines in the supernova SN 1987a

    NASA Astrophysics Data System (ADS)

    Lehoucq, R.; Durouchouxa, Ph.

    Using a Monte Carlo code, gamma-ray lines produced by 56Co, 57Co and 44Ti are studied in terms of photon transport inside the envelope of the SN 1987a. Computations are compared with gamma-ray observations conducted by 8 different groups during three years. The results, mainly the line shifts and the line widths of 56Co lines put constraints on the models, in terms of mixing and fragmentation. An estimation of the predicted fluxes of 57Co and 44Ti lines and its effects on the bolometric light curve is presented. En utilisant une méthode de Monte-Carlo, nous avons étudié le transfert de photons de haute énergie dans l'enveloppe de la supernova SN 1987a, en nous intéressant particulièrement aux rayons gammas émis par la désintégration de noyaux radioactifs tels que le 56Co, le 57Co et le 44Ti. Nos calculs sont comparés avec les observations gammas réalisées par huit groupes differents pendant trois ans. Les résultats, concernant principalement les largeurs et les décalages des raies du 56Co, imposent des contraintes sur les modèles et notamment sur le mélange et la fragmentation au sein de l'enveloppe. Nous présentons aussi des prédictions sur le flux des raies du 57Co et du 44Ti ainsi qu'une estimation de leur influence sur la courbe de lumière bolométrique.

  12. VLBI observations of SN 2011dh: imaging of the youngest radio supernova

    NASA Astrophysics Data System (ADS)

    Martí-Vidal, I.; Tudose, V.; Paragi, Z.; Yang, J.; Marcaide, J. M.; Guirado, J. C.; Ros, E.; Alberdi, A.; Pérez-Torres, M. A.; Argo, M. K.; van der Horst, A. J.; Garrett, M. A.; Stockdale, C. J.; Weiler, K. W.

    2011-11-01

    We report on the VLBI detection of supernova SN 2011dh at 22 GHz using a subset of the EVN array. The observations took place 14 days after the discovery of the supernova, thus resulting in a VLBI image of the youngest radio-loud supernova ever. We provide revised coordinates for the supernova with milli-arcsecond precision, linked to the ICRF. The recovered flux density is a factor ~2 below the EVLA flux density reported by other authors at the same frequency and epoch of our observations. This discrepancy could be due to extended emission detected with the EVLA or to calibration problems in the VLBI and/or EVLA observations.

  13. Superluminous Supernova SN 2015bn in the Nebular Phase: Evidence for the Engine-powered Explosion of a Stripped Massive Star

    NASA Astrophysics Data System (ADS)

    Nicholl, M.; Berger, E.; Margutti, R.; Chornock, R.; Blanchard, P. K.; Jerkstrand, A.; Smartt, S. J.; Arcavi, I.; Challis, P.; Chambers, K. C.; Chen, T.-W.; Cowperthwaite, P. S.; Gal-Yam, A.; Hosseinzadeh, G.; Howell, D. A.; Inserra, C.; Kankare, E.; Magnier, E. A.; Maguire, K.; Mazzali, P. A.; McCully, C.; Milisavljevic, D.; Smith, K. W.; Taubenberger, S.; Valenti, S.; Wainscoat, R. J.; Yaron, O.; Young, D. R.

    2016-09-01

    We present nebular-phase imaging and spectroscopy for the hydrogen-poor superluminous supernova (SLSN) SN 2015bn, at redshift z = 0.1136, spanning +250–400 days after maximum light. The light curve exhibits a steepening in the decline rate from 1.4 mag (100 days)‑1 to 1.7 mag (100 days)‑1, suggestive of a significant decrease in the opacity. This change is accompanied by a transition from a blue continuum superposed with photospheric absorption lines to a nebular spectrum dominated by emission lines of oxygen, calcium, and magnesium. There are no obvious signatures of circumstellar interaction or large 56Ni mass. We show that the spectrum at +400 days is virtually identical to a number of energetic SNe Ic such as SN 1997dq, SN 2012au, and SN 1998bw, indicating similar core conditions and strengthening the link between “hypernovae”/long gamma-ray bursts and SLSNe. A single explosion mechanism may unify these events that span absolute magnitudes of ‑22 < M B < ‑17. Both the light curve and spectrum of SN 2015bn are consistent with an engine-driven explosion ejecting 7–30 M ⊙ of oxygen-dominated ejecta (for reasonable choices in temperature and opacity). A strong and relatively narrow O i λ7774 line, seen in a number of these energetic events but not in normal supernovae, may point to an inner shell that is the signature of a central engine.

  14. A massive hypergiant star as the progenitor of the supernova SN 2005gl.

    PubMed

    Gal-Yam, A; Leonard, D C

    2009-04-16

    Our understanding of the evolution of massive stars before their final explosions as supernovae is incomplete, from both an observational and a theoretical standpoint. A key missing piece in the supernova puzzle is the difficulty of identifying and studying progenitor stars. In only a single case-that of supernova SN 1987A in the Large Magellanic Cloud-has a star been detected at the supernova location before the explosion, and been subsequently shown to have vanished after the supernova event. The progenitor of SN 1987A was a blue supergiant, which required a rethink of stellar evolution models. The progenitor of supernova SN 2005gl was proposed to be an extremely luminous object, but the association was not robustly established (it was not even clear that the putative progenitor was a single luminous star). Here we report that the previously proposed object was indeed the progenitor star of SN 2005gl. This very massive star was likely a luminous blue variable that standard stellar evolution predicts should not have exploded in that state. PMID:19305392

  15. Late Light Curves of SN 2002cx-like Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Lair, Jessica C.; Kilgore, E. E.; Milne, P.; Bryngelson, G. L.; Leising, M. D.

    2013-01-01

    The use of Type Ia Supernovae (SNe Ia) in cosmological studies as “standard candle” distance indicators lead to the need for a better understanding of these objects. SN 2002cx was a very peculiar SNe Ia that did not fit into any of the known subclasses of SNe Ia and needs to be further understood. We present late-time optical photometry of three more recently discovered objects that have been determined to be SN 2002cx-like Type Ia supernovae: SN 2005hk, SN 2008A, and SN 2008ae. The light curves of these objects show late-time decline rates that are slower than what is seen in normal SNe Ia in the V,R, and I bands, but faster in the B-band.

  16. The Metamorphosis of Supernova SN 2008D/XRF 080109: A Link Between Supernovae and GRBs/Hypernovae

    NASA Astrophysics Data System (ADS)

    Mazzali, Paolo A.; Valenti, Stefano; Della Valle, Massimo; Chincarini, Guido; Sauer, Daniel N.; Benetti, Stefano; Pian, Elena; Piran, Tsvi; D'Elia, Valerio; Elias-Rosa, Nancy; Margutti, Raffaella; Pasotti, Francesco; Antonelli, L. Angelo; Bufano, Filomena; Campana, Sergio; Cappellaro, Enrico; Covino, Stefano; D'Avanzo, Paolo; Fiore, Fabrizio; Fugazza, Dino; Gilmozzi, Roberto; Hunter, Deborah; Maguire, Kate; Maiorano, Elisabetta; Marziani, Paola; Masetti, Nicola; Mirabel, Felix; Navasardyan, Hripsime; Nomoto, Ken'ichi; Palazzi, Eliana; Pastorello, Andrea; Panagia, Nino; Pellizza, L. J.; Sari, Re'em; Smartt, Stephen; Tagliaferri, Gianpiero; Tanaka, Masaomi; Taubenberger, Stefan; Tominaga, Nozomu; Trundle, Carrie; Turatto, Massimo

    2008-08-01

    The only supernovae (SNe) to show gamma-ray bursts (GRBs) or early x-ray emission thus far are overenergetic, broad-lined type Ic SNe (hypernovae, HNe). Recently, SN 2008D has shown several unusual features: (i) weak x-ray flash (XRF), (ii) an early, narrow optical peak, (iii) disappearance of the broad lines typical of SN Ic HNe, and (iv) development of helium lines as in SNe Ib. Detailed analysis shows that SN 2008D was not a normal supernova: Its explosion energy (E ≈ 6 × 1051 erg) and ejected mass [~7 times the mass of the Sun (M◉)] are intermediate between normal SNe Ibc and HNe. We conclude that SN 2008D was originally a ~30 M◉ star. When it collapsed, a black hole formed and a weak, mildly relativistic jet was produced, which caused the XRF. SN 2008D is probably among the weakest explosions that produce relativistic jets. Inner engine activity appears to be present whenever massive stars collapse to black holes.

  17. The metamorphosis of supernova SN 2008D/XRF 080109: a link between supernovae and GRBs/hypernovae.

    PubMed

    Mazzali, Paolo A; Valenti, Stefano; Della Valle, Massimo; Chincarini, Guido; Sauer, Daniel N; Benetti, Stefano; Pian, Elena; Piran, Tsvi; D'Elia, Valerio; Elias-Rosa, Nancy; Margutti, Raffaella; Pasotti, Francesco; Antonelli, L Angelo; Bufano, Filomena; Campana, Sergio; Cappellaro, Enrico; Covino, Stefano; D'Avanzo, Paolo; Fiore, Fabrizio; Fugazza, Dino; Gilmozzi, Roberto; Hunter, Deborah; Maguire, Kate; Maiorano, Elisabetta; Marziani, Paola; Masetti, Nicola; Mirabel, Felix; Navasardyan, Hripsime; Nomoto, Ken'ichi; Palazzi, Eliana; Pastorello, Andrea; Panagia, Nino; Pellizza, L J; Sari, Re'em; Smartt, Stephen; Tagliaferri, Gianpiero; Tanaka, Masaomi; Taubenberger, Stefan; Tominaga, Nozomu; Trundle, Carrie; Turatto, Massimo

    2008-08-29

    The only supernovae (SNe) to show gamma-ray bursts (GRBs) or early x-ray emission thus far are overenergetic, broad-lined type Ic SNe (hypernovae, HNe). Recently, SN 2008D has shown several unusual features: (i) weak x-ray flash (XRF), (ii) an early, narrow optical peak, (iii) disappearance of the broad lines typical of SN Ic HNe, and (iv) development of helium lines as in SNe Ib. Detailed analysis shows that SN 2008D was not a normal supernova: Its explosion energy (E approximately 6x10(51) erg) and ejected mass [ approximately 7 times the mass of the Sun (M(middle dot in circle))] are intermediate between normal SNe Ibc and HNe. We conclude that SN 2008D was originally a approximately 30 M(middle dot in circle) star. When it collapsed, a black hole formed and a weak, mildly relativistic jet was produced, which caused the XRF. SN 2008D is probably among the weakest explosions that produce relativistic jets. Inner engine activity appears to be present whenever massive stars collapse to black holes. PMID:18653846

  18. The Final Word on the Progenitor of the Type II-Plateau Supernova SN 2006ov

    NASA Astrophysics Data System (ADS)

    Leonard, Douglas

    2011-10-01

    Despite recent rapid progress, the field of supernova {SN} progenitor identification remains in its infancy, with only five supernovae having had unambiguous detection and characterization of their progenitor stars made. The existence of deep pre-SN WFPC2 images of the site of the nearby core-collapse {Type II-Plateau} SN 2006ov has enabled two independent searches for its progenitor star to be carried out. While both studies agree that an object is located at the location of SN 2006ov in the pre-SN images, they disagree on whether the light from this source {or, part of it} is, in fact, coming from the actual progenitor star. The time is ripe to settle the issue: A single-orbit reobservation of the SN site with HST/ACS will permit the definitive determination of whether this object is indeed associated with SN 2006ov. If it is, and its flux is found to have diminished {it was an extended source} or vanished {it was an isolated star}, then this will enable the third conclusive characterization of a Type II-Plateau supernova's progenitor star's properties to be made. If it is not, then a firm upper mass limit on the progenitor star will be confidently declared the final word on the topic.

  19. Nearby Supernova Factory Observations of SN 2005gj: Another TypeIa Supernova in a Massive Circumstellar Envelope

    SciTech Connect

    Aldering, G.; Antilogus, P.; Bailey, S.; Baltay, C.; Bauer, A.; Blanc, N.; Bongard, S.; Copin, Y.; Gangler, E.; Gilles, S.; Kessler, R.; Kocevski, D.; Lee, B.C.; Loken, S.; Nugent, P.; Pain, R.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigaudier, G.; Scalzo, R.; Smadja, G.; Thomas, R.C.; Wang, L.; Weaver, B.A.; Rabinowitz, D.; Bauer, A.

    2006-06-01

    We report the independent discovery and follow-up observations of supernova 2005gj by the Nearby Supernova Factory. This is the second confirmed case of a ''hybrid'' Type Ia/IIn supernova, which like the prototype SN 2002ic, we interpret as the explosion of a white dwarf interacting with a circumstellar medium. Our early-phase photometry of SN 2005gj shows that the strength of the interaction between the supernova ejecta and circumstellar material is much stronger than for SN 2002ic. Our .rst spectrum shows a hot continuum with broad and narrow H{alpha} emission. Later spectra, spanning over 4 months from outburst, show clear Type Ia features combined with broad and narrow H{gamma}, H{beta},H{alpha} and He I {lambda}{lambda}5876,7065 in emission. At higher resolution, P Cygni profiles are apparent. Surprisingly, we also observe an inverted P Cygni profile for [O III] {lambda}5007. We find that the lightcurve and measured velocity of the unshocked circumstellar material imply mass loss as recently as 8 years ago. This is in contrast to SN 2002ic, for which an inner cavity in the circumstellar material was inferred. Within the context of the thin-shell approximation, the early lightcurve is well-described by a flat radial density profile for the circumstellar material. However, our decomposition of the spectra into Type Ia and shock emission components allows for little obscuration of the supernova, suggesting an aspherical or clumpy distribution for the circumstellar material. We suggest that the emission line velocity profiles arise from electron scattering rather than the kinematics of the shock. This is supported by the inferred high densities, and the lack of evidence for evolution in the line widths. Ground- and space-based photometry, and Keck spectroscopy, of the host galaxy are used to ascertain that the host galaxy has low metallicity (Z/Z{sub {circle_dot}} < 0.3; 95% confidence) and that this galaxy is undergoing a significant star formation event that

  20. CONSTRAINING TYPE Ia SUPERNOVA MODELS: SN 2011fe AS A TEST CASE

    SciTech Connect

    Roepke, F. K.; Seitenzahl, I. R.; Kromer, M.; Taubenberger, S.; Ciaraldi-Schoolmann, F.; Hillebrandt, W.; Benitez-Herrera, S.; Pakmor, R.; Sim, S. A.; Aldering, G.; Childress, M.; Fakhouri, H. K.; Antilogus, P.; Bongard, S.; Canto, A.; Cellier-Holzem, F.; Baltay, C.; Buton, C.; Chotard, N.; Copin, Y. [Universite de Lyon, F-69622, Lyon; Universite de Lyon 1, Villeurbanne; CNRS and others

    2012-05-01

    The nearby supernova SN 2011fe can be observed in unprecedented detail. Therefore, it is an important test case for Type Ia supernova (SN Ia) models, which may bring us closer to understanding the physical nature of these objects. Here, we explore how available and expected future observations of SN 2011fe can be used to constrain SN Ia explosion scenarios. We base our discussion on three-dimensional simulations of a delayed detonation in a Chandrasekhar-mass white dwarf and of a violent merger of two white dwarfs (WDs)-realizations of explosion models appropriate for two of the most widely discussed progenitor channels that may give rise to SNe Ia. Although both models have their shortcomings in reproducing details of the early and near-maximum spectra of SN 2011fe obtained by the Nearby Supernova Factory (SNfactory), the overall match with the observations is reasonable. The level of agreement is slightly better for the merger, in particular around maximum, but a clear preference for one model over the other is still not justified. Observations at late epochs, however, hold promise for discriminating the explosion scenarios in a straightforward way, as a nucleosynthesis effect leads to differences in the {sup 55}Co production. SN 2011fe is close enough to be followed sufficiently long to study this effect.

  1. The Energetics and Environments of Type Ibc Supernovae

    NASA Astrophysics Data System (ADS)

    Soderberg, Alicia

    2013-09-01

    Twenty-five years have passed since the peculiar class of Type Ibc supernovae were first recognized as a distinct flavor of core-collapse explosions. Their low volumetric rate and optical heterogeneity did not initially motivate strong observational programs. SNe Ibc have enjoyed a surge of interest thanks to the observational realization that most long-duration gamma-ray bursts (GRBs) are accompanied by SNe Ibc. The converse, however, is not true: we recently measured the fraction of SNe Ibc harboring relativistic GRB jets to be just 1%. The progenitors of SNe Ibc and their relation to those of GRB-SNe have yet to be observationally identified. Here we propose a modest Chandra program to enable progress.

  2. A Missing-link in the Supernova-GRB Connection: The Case of SN 2012ap

    NASA Astrophysics Data System (ADS)

    Chakraborti, Sayan; Soderberg, Alicia; Chomiuk, Laura; Kamble, Atish; Yadav, Naveen; Ray, Alak; Hurley, Kevin; Margutti, Raffaella; Milisavljevic, Dan; Bietenholz, Michael; Brunthaler, Andreas; Pignata, Giuliano; Pian, Elena; Mazzali, Paolo; Fransson, Claes; Bartel, Norbert; Hamuy, Mario; Levesque, Emily; MacFadyen, Andrew; Dittmann, Jason; Krauss, Miriam; Briggs, M. S.; Connaughton, V.; Yamaoka, K.; Takahashi, T.; Ohno, M.; Fukazawa, Y.; Tashiro, M.; Terada, Y.; Murakami, T.; Goldsten, J.; Barthelmy, S.; Gehrels, N.; Cummings, J.; Krimm, H.; Palmer, D.; Golenetskii, S.; Aptekar, R.; Frederiks, D.; Svinkin, D.; Cline, T.; Mitrofanov, I. G.; Golovin, D.; Litvak, M. L.; Sanin, A. B.; Boynton, W.; Fellows, C.; Harshman, K.; Enos, H.; von Kienlin, A.; Rau, A.; Zhang, X.; Savchenko, V.

    2015-06-01

    Gamma-ray bursts (GRBs) are characterized by ultra-relativistic outflows, while supernovae are generally characterized by non-relativistic ejecta. GRB afterglows decelerate rapidly, usually within days, because their low-mass ejecta rapidly sweep up a comparatively larger mass of circumstellar material. However, supernovae with heavy ejecta can be in nearly free expansion for centuries. Supernovae were thought to have non-relativistic outflows except for a few relativistic ones accompanied by GRBs. This clear division was blurred by SN 2009bb, the first supernova with a relativistic outflow without an observed GRB. However, the ejecta from SN 2009bb was baryon loaded and in nearly free expansion for a year, unlike GRBs. We report the first supernova discovered without a GRB but with rapidly decelerating mildly relativistic ejecta, SN 2012ap. We discovered a bright and rapidly evolving radio counterpart driven by the circumstellar interaction of the relativistic ejecta. However, we did not find any coincident GRB with an isotropic fluence of more than one-sixth of the fluence from GRB 980425. This shows for the first time that central engines in SNe Ic, even without an observed GRB, can produce both relativistic and rapidly decelerating outflows like GRBs.

  3. The Final Word on the Progenitor of the Type II-Plateau Supernova SN 2006my

    NASA Astrophysics Data System (ADS)

    Leonard, Douglas

    2010-09-01

    Despite recent rapid progress, the field of supernova {SN} progenitor identification remains in its infancy, with only four supernovae having had unambiguous detection and characterization of their progenitor stars made. The existence of pre-SN WFPC2 images of the site of the nearby core-collapse {Type II-Plateau} SN 2006my has enabled three independent searches for its progenitor star to be carried out. In the first, Li et. al. {2007} find spatial coincidence between the SN and a possibly extended source with properties deemed consistent with those of a red supergiant. Subsequent analyses by Leonard et al. {2008} and Crockett et al. {2010} refute the Li et al. detection claim, but recognize that existing data do not permit a definitive resolution of the issue since even the revised SN localizations place SN 2006my on part of the putative progenitor's point-spread-function in the pre-SN frames {although no longer at its center}. The time is ripe to settle the issue: A single-orbit reobservation of the SN site with HST/ACS will permit the definitive determination of whether this object is indeed associated with SN 2006my. If it is, and its flux is found to have diminished {it was an extended source} or vanished {it was an isolated star}, then this will enable the second conclusive characterization of a Type II-Plateau supernova's progenitor star's properties to be made. If it is not, then upper mass limits on the progenitor star will be confidently declared the final word on the topic.

  4. Spectroscopic Classification of SN 2016bll (=PTSS-16ckr) as a Type Ib Supernova

    NASA Astrophysics Data System (ADS)

    Rui, Liming; Wang, Xiaofeng; Li, Wenxiong; Yang, Zesheng; Li, Bin; Zhao, Haibin; Wang, Lifan; Xu, Zhijian; Zhang, Jujia; Zhang, Tianmeng

    2016-04-01

    We obtained an optical spectrum (range 420-860 nm) of SN 2016bll(=PTSS-16ckr), discovered by the PMO-Tsinghua Supernova Survey (PTSS: http://119.78.210.3/ptss2/ ), on UT Apr.04.7 2016 with the 2.16-m telescope (+BFOSC) at Xinglong Station of National Astronomical Observatories of China (NAOC).

  5. Spectroscopic Classification of SN 2016bla (PTSS-16bwt) as a Type IIP Supernova

    NASA Astrophysics Data System (ADS)

    Zhang, Jujia; Lun, Baoli; Wang, Xiaofeng; Li, Wenxiong; Yang, Zesheng; Li, Bin; Zhao, Haibin; Wang, Lifan; Xu, Zhijian

    2016-03-01

    We obtained an optical spectrum (range 330-880 nm) of SN 2016ayg, discovered by the PMO-Tsinghua Supernova Survey (PTSS: http://119.78.210.3/ptss2/), on UT Mar.30.6 2016 with the 2.4-m telescope (+YFOSC) at LiJiang Gaomeigu Station of Yunnan Astronomical Observatories (YNAO).

  6. Spectroscopic Classification of SN 2016cdg (=PTSS-16gif) as a Type Ia Supernova

    NASA Astrophysics Data System (ADS)

    Zhang, Jujia; Yi, Weimin; Wang, Xiaofeng; Li, Wenxiong; Yang, Zesheng; Li, Bin; Xu, Zhijian; Zhao, Haibin; Wang, Lifan

    2016-05-01

    We obtained an optical spectrum (range 340-900 nm) of SN 2016cdg (=PTSS-16gif), discovered by the PMO-Tsinghua Supernova Survey (PTSS: http://119.78.210.3/ptss2/), on UT May 19.75 2016 with the 2.4 m telescope ( LJT + YFOSC) at LiJiang Observatory of Yunnan Observatories (YNAO).

  7. Spectroscopic Classification of SN 2016bkz (=PTSS-16brc) as a Type IIP Supernova

    NASA Astrophysics Data System (ADS)

    Zhang, Jujia; Lun, Baoli; Wang, Xiaofeng; Li, Wenxiong; Yang, Zesheng; Li, Bin; Zhao, Haibin; Wang, Lifan; Xu, Zhijian

    2016-04-01

    We obtained an optical spectrum (range 350-900 nm) of SN 2016bkz(=PTSS-16brc), discovered by the PMO-Tsinghua Supernova Survey (PTSS: http://119.78.210.3/ptss2/), on UT Mar.31.6 2016 with the 2.4-m telescope (+YFOSC) at LiJiang Gaomeigu Station of Yunnan Astronomical Observatories (YNAO).

  8. Spectroscopic Classification of SN 2016bly (=PTSS16-cuh) as a Type IIn Supernova

    NASA Astrophysics Data System (ADS)

    Zhang, Jujia; Wang, Chuanjun; Wang, Xiaofeng; Li, Wenxiong; Yang, Zesheng; Li, Bin; Xu, Zhijian; Zhao, Haibin; Wang, Lifan

    2016-04-01

    We obtained an optical spectrum (range 340-900 nm) of SN 2016bly (=PTSS-16cuh), discovered by the PMO-Tsinghua Supernova Survey (PTSS: http://119.78.210.3/ptss2/ ), on UT Apr.10.8 2016 with the 2.4-m telescope (+YFOSC) at LiJiang Gaomeigu Station of Yunnan Astronomical Observatories (YNAO).

  9. Spectroscopic Classification of SN 2016blh (=PTSS-16cfg) as a Type Ia Supernova

    NASA Astrophysics Data System (ADS)

    Zhang, Jujia; Zheng, Xiangming; Wang, Xiaofeng; Li, Wenxiong; Yang, Zesheng; Xu, Zhijian; Li, Bin; Zhao, Haibin; Wang, Lifan

    2016-04-01

    We obtained an optical spectrum (range 340-890 nm) of SN 2016blh(=PTSS-16cfg), discovered by the PMO-Tsinghua Supernova Survey (PTSS: http://119.78.210.3/ptss2/ ), on UT Apr.03.7 2016 with the 2.4-m telescope (+YFOSC) at LiJiang Gaomeigu Station of Yunnan Astronomical Observatories (YNAO).

  10. Spectroscopic Classification of AT SN 2016cce (=PTSS-16dzd) as a Type Ia Supernova

    NASA Astrophysics Data System (ADS)

    Zhang, Jujia; Zhang, Xiliang; Wang, Xiaofeng; Li, Wenxiong; Yang, Zesheng; Li, Bin; Xu, Zhijian; Zhao, Haibin; Wang, Lifan

    2016-05-01

    We obtained an optical spectrum (range 345-910 nm) of SN 2016cce (=PTSS-16dzd), discovered by the PMO-Tsinghua Supernova Survey (PTSS: http://119.78.210.3/ptss2/ ), on UT Apr.30.7 2016 with the 2.4-m telescope (+YFOSC) at LiJiang Gaomeigu Station of Yunnan Astronomical Observatories (YNAO).

  11. Spectroscopic Classification of SN 2016cck (=PTSS-16efw) as a Type Ia Supernova

    NASA Astrophysics Data System (ADS)

    Zhang, Jujia; Wang, Jianguo; Wang, Xiaofeng; Li, Wenxiong; Yang, Zesheng; Li, Bin; Xu, Zhijian; Zhao, Haibin; Wang, Lifan

    2016-05-01

    We obtained an optical spectrum (range 340-900 nm) of SN 2016cck (=PTSS-16efw), discovered by the PMO-Tsinghua Supernova Survey (PTSS: http://119.78.210.3/ptss2/), on UT May 05.8 2016 with the 2.4 m telescope ( LJT + YFOSC) at LiJiang Observatory of Yunnan Observatories (YNAO).

  12. Spectroscopic Classification of SN 2016cdg (=PTSS-16gyb) as a Type Ia Supernova

    NASA Astrophysics Data System (ADS)

    Zhang, Jujia; Zheng, Xiangming; Wang, Xiaofeng; Li, Wenxiong; Yang, Zesheng; Li, Bin; Xu, Zhijian; Zhao, Haibin; Wang, Lifan

    2016-05-01

    We obtained an optical spectrum (range 340-900 nm) of SN 2016cnv (=PTSS-16gif), discovered by the PMO-Tsinghua Supernova Survey (PTSS: http://119.78.210.3/ptss2/), on UT May 26.71 2016 with the 2.4 m telescope (LJT + YFOSC) at LiJiang Observatory of Yunnan Observatories (YNAO).

  13. Spectrocopic Classification of SN 2016ayg (PTSS-16hs) as a Type Ia Supernova

    NASA Astrophysics Data System (ADS)

    Zhang, Jujia; Wang, Xiaofeng; Li, Wenxiong; Yang, Zesheng; Li, Bin; Zhao, Haibin; Wang, Lifan

    2016-03-01

    We obtained an optical spectrum (range 330-880 nm) of SN 2016ayg, discovered by the PMO-Tsinghua Supernova Survey (PTSS), on UT Mar.12.6 2016 with the 2.4-m telescope (+YFOSC) at LiJiang Gaomeigu Station of Yunnan Astronomical Observatories (YNAO).

  14. Spectroscopic Classification of SN 2016blg (=PTSS-16cfd) as a Type Ia Supernova

    NASA Astrophysics Data System (ADS)

    Zhang, Jujia; Zheng, Xiangming; Wang, Xiaofeng; Li, Wenxiong; Rui, Liming; Yang, Zesheng; Xu, Zhijian; Li, Bin; Zhao, Haibin; Wang, Lifan

    2016-04-01

    We obtained an optical spectrum (range 320-850 nm) of SN 2016blg(=PTSS-16cfd), discovered by the PMO-Tsinghua Supernova Survey (PTSS: http://119.78.210.3/ptss2/ ), on UT Apr.04.7 2016 with the 2.4-m telescope (+YFOSC) at LiJiang Gaomeigu Station of Yunnan Astronomical Observatories (YNAO).

  15. Spectroscopic Classification of SN 2016cyi as a Type IIn Supernova

    NASA Astrophysics Data System (ADS)

    Rui, Liming; Lin, Han; Wang, Xiaofeng; Li, Wenxiong; Yang, Zesheng; Li, Bin; Xu, Zhijian; Zhao, Haibin; Wang, Lifan; Zhang, Jujia; Zhang, Tianmeng

    2016-08-01

    We obtained an optical spectrum (range 370-840 nm) of SN 2016cyi (=PTSS-16jik), discovered by the PMO-Tsinghua Supernova Survey (PTSS: http://119.78.210.3/ptss2/), on UT Aug.02.7 2016 with the 2.16-m telescope (+BFOSC) at Xinglong Station of National Astronomical Observatories of China (NAOC).

  16. Supernova SN1987A in the Large Magellanic Cloud

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Glittering stars and wisps of gas create a breathtaking backdrop for the self-destruction of a massive star, called supernova 1987A, in the Large Magellanic Cloud, a nearby galaxy. Astronomers in the Southern hemisphere witnessed the brilliant explosion of this star on Feb. 23, 1987. Shown in this NASA Hubble Space Telescope image, the supernova remnant, surrounded by inner and outer rings of material, is set in a forest of ethereal, diffuse clouds of gas. This three-color image is composed of several pictures of the supernova and its neighboring region taken with the Wide Field and Planetary Camera 2 in Sept. 1994, Feb. 1996 and July 1997. The many bright blue stars nearby the supernova are massive stars, each more than six times heftier than our Sun. They are members of the same generation of stars as the star that went supernova about 12 million years ago. The presence of bright gas clouds is another sign of the youth of this region, which still appears to be a fertile breeding ground for new stars. In a few years the supernova's fast moving material will sweep the inner ring with full force, heating and exciting its gas, and will produce a new series of cosmic fireworks that will offer a striking view for more than a decade.

  17. Upper limits on the luminosity of the progenitor of Type Ia supernova SN 2014J

    NASA Astrophysics Data System (ADS)

    Nielsen, M. T. B.; Gilfanov, M.; Bogdán, Á.; Woods, T. E.; Nelemans, G.

    2014-08-01

    We analysed archival data of Chandra pre-explosion observations of the position of SN 2014J in M82. No X-ray source at this position was detected in the data, and we calculated upper limits on the luminosities of the progenitor. These upper limits allow us to firmly rule out an unobscured supersoft X-ray source progenitor with a photospheric radius comparable to the radius of white dwarf near the Chandrasekhar mass (˜1.38 M⊙) and mass accretion rate in the interval where stable nuclear burning can occur. However, due to a relatively large hydrogen column density implied by optical observations of the supernova, we cannot exclude a supersoft source with lower temperatures, kT ≲ 70 eV. We find that the supernova is located in the centre of a large structure of soft diffuse emission, about 200 pc across. The mass, ˜3 × 104 M⊙ and short cooling time of the gas, τcool ˜ 8 Myr, suggest that it is a supernova-inflated superbubble, associated with the region of recent star formation. If SN 2014J is indeed located inside the bubble, it likely belongs to the prompt population of Type Ia supernovae, with a delay time as short as ˜50 Myr. Finally, we analysed the one existing post-supernova Chandra observation and placed upper limit of ˜(1-2) × 1037 erg s-1 on the X-ray luminosity of the supernova itself.

  18. SN 2011fe: A Laboratory for Testing Models of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Chomiuk, Laura

    2013-08-01

    SN 2011fe is the nearest supernova of Type Ia (SN Ia) discovered in the modern multi-wavelength telescope era, and it also represents the earliest discovery of an SN Ia to date. As a normal SN Ia, SN 2011fe provides an excellent opportunity to decipher long-standing puzzles about the nature of SNe Ia. In this review, we summarise the extensive suite of panchromatic data on SN 2011fe and gather interpretations of these data to answer four key questions: (1) What explodes in an SN Ia? (2) How does it explode? (3) What is the progenitor of SN 2011fe? and (4) How accurate are SNe Ia as standardisable candles? Most aspects of SN 2011fe are consistent with the canonical picture of a massive CO white dwarf undergoing a deflagration-to-detonation transition. However, there is minimal evidence for a non-degenerate companion star, so SN 2011fe may have marked the merger of two white dwarfs.

  19. An asymmetric energetic type Ic supernova viewed off-axis, and a link to gamma ray bursts.

    PubMed

    Mazzali, Paolo A; Kawabata, Koji S; Maeda, Keiichi; Nomoto, Ken'ichi; Filippenko, Alexei V; Ramirez-Ruiz, Enrico; Benetti, Stefano; Pian, Elena; Deng, Jinsong; Tominaga, Nozomu; Ohyama, Youichi; Iye, Masanori; Foley, Ryan J; Matheson, Thomas; Wang, Lifan; Gal-Yam, Avishay

    2005-05-27

    Type Ic supernovae, the explosions after the core collapse of massive stars that have previously lost their hydrogen and helium envelopes, are particularly interesting because of their link with long-duration gamma ray bursts. Although indications exist that these explosions are aspherical, direct evidence has been missing. Late-time observations of supernova SN 2003jd, a luminous type Ic supernova, provide such evidence. Recent Subaru and Keck spectra reveal double-peaked profiles in the nebular lines of neutral oxygen and magnesium. These profiles are different from those of known type Ic supernovae, with or without a gamma ray burst, and they can be understood if SN 2003jd was an aspherical axisymmetric explosion viewed from near the equatorial plane. If SN 2003jd was associated with a gamma ray burst, we missed the burst because it was pointing away from us. PMID:15919986

  20. SN 2008ha: AN EXTREMELY LOW LUMINOSITY AND EXCEPTIONALLY LOW ENERGY SUPERNOVA

    SciTech Connect

    Foley, Ryan J.; Kirshner, Robert P.; Challis, Peter J.; Friedman, Andrew S.; Chornock, Ryan; Filippenko, Alexei V.; Ganeshalingam, Mohan; Li, Weidong; Cenko, S. Bradley; Modjaz, Maryam; Silverman, Jeffrey M.; Wood-Vasey, W. Michael

    2009-08-15

    We present ultraviolet, optical, and near-infrared photometry as well as optical spectra of the peculiar supernova (SN) 2008ha. SN 2008ha had a very low peak luminosity, reaching only M{sub V} = -14.2 mag, and low line velocities of only {approx}2000 km s{sup -1} near maximum brightness, indicating a very small kinetic energy per unit mass of ejecta. Spectroscopically, SN 2008ha is a member of the SN 2002cx-like class of SNe, a peculiar subclass of SNe Ia; however, SN 2008ha is the most extreme member, being significantly fainter and having lower line velocities than the typical member, which is already {approx}2 mag fainter and has line velocities {approx}5000 km s{sup -1} smaller (near maximum brightness) than a normal SN Ia. SN 2008ha had a remarkably short rise time of only {approx}10 days, significantly shorter than either SN 2002cx-like objects ({approx}15 days) or normal SNe Ia ({approx}19.5 days). The bolometric light curve of SN 2008ha indicates that SN 2008ha peaked at L {sub peak} = (9.5 {+-} 1.4) x 10{sup 40} erg s{sup -1}, making SN 2008ha perhaps the least luminous SN ever observed. From its peak luminosity and rise time, we infer that SN 2008ha generated (3.0 {+-} 0.9) x 10{sup -3} M {sub sun} of {sup 56}Ni, had a kinetic energy of {approx}2 x 10{sup 48} erg, and ejected 0.15 M {sub sun} of material. The host galaxy of SN 2008ha has a luminosity, star formation rate, and metallicity similar to those of the Large magellanic Cloud. We classify three new (and one potential) members of the SN 2002cx-like class, expanding the sample to 14 (and one potential) members. The host-galaxy morphology distribution of the class is consistent with that of SNe Ia, Ib, Ic, and II. Several models for generating low-luminosity SNe can explain the observations of SN 2008ha; however, if a single model is to describe all SN 2002cx-like objects, deflagration of carbon-oxygen white dwarfs, with SN 2008ha being a partial deflagration and not unbinding the progenitor star, is

  1. SN 1991bg - A type Ia supernova with a difference

    NASA Technical Reports Server (NTRS)

    Leibundgut, Bruno; Kirshner, Robert P.; Phillips, Mark M.; Wells, Lisa A.; Suntzeff, N. B.; Hamuy, Mario; Schommer, R. A.; Walker, A. R.; Gonzalez, L.; Ugarte, P.

    1993-01-01

    While SN 1991bg is an unusual type Ia SN in such a feature as the brief duration of the photospheric phase, which ended only two weeks after maximum, it shares with other Ia SNs strong Si II and Ca II lines near maximum light. In addition, the light and color curve slopes are almost identical with the templates at late times. The spectral evolution of SN 1991bg is also unique but not unrecognizable; nevertheless, the peculiarities associated with this event complicate the fundamental question as to whether the Ia SNs make good standard candles.

  2. SN 2008S: A Cool Super-Eddington Wind in a Supernova Impostor

    NASA Astrophysics Data System (ADS)

    Smith, Nathan; Ganeshalingam, Mohan; Chornock, Ryan; Filippenko, Alexei V.; Li, Weidong; Silverman, Jeffrey M.; Steele, Thea N.; Griffith, Christopher V.; Joubert, Niels; Lee, Nicholas Y.; Lowe, Thomas B.; Mobberley, Martin P.; Winslow, Dustin M.

    2009-05-01

    We present visual-wavelength photometry and spectroscopy of supernova (SN) 2008S. Based on the low peak luminosity for a SN of MR = -13.9 mag, photometric and spectral evolution unlike that of low-luminosity SNe, a late-time decline rate slower than 56Co decay, and slow outflow speeds of 600-1000 km s-1, we conclude that SN 2008S is not a true core-collapse SN and is probably not an electron-capture SN. Instead, we show that SN 2008S more closely resembles an "SN impostor" event like SN 1997bs, analogous to the giant eruptions of luminous blue variables (LBVs). Its total radiated energy was ~1047.8 erg, and it may have ejected 0.05-0.2 M sun in the event. We discover an uncanny similarity between the spectrum of SN 2008S and that of the Galactic hypergiant IRC+10420, which is dominated by narrow Hα, [Ca II], and Ca II emission lines formed in an opaque wind. We propose a scenario where the vastly super-Eddington (Γ ≈ 40) wind of SN 2008S partly fails because of reduced opacity due to recombination, as suggested for IRC+10420. The range of initial masses susceptible to eruptive LBV-like mass loss was known to extend down to 20-25 M sun, but estimates for the progenitor of SN 2008S (and the similar NGC 300 transient) may extend this range to lsim15 M sun. As such, SN 2008S may have implications for the progenitor of SN 1987A.

  3. Optical observations of an SN 2002cx-like peculiar supernova SN 2013en in UGC 11369

    NASA Astrophysics Data System (ADS)

    Liu, Zheng-Wei; Zhang, J.-J.; Ciabattari, F.; Tomasella, L.; Wang, X.-F.; Zhao, X.-L.; Zhang, T.-M.; Xin, Y.-X.; Wang, C.-J.; Chang, L.

    2015-09-01

    We present optical observations of an SN 2002cx-like supernova SN 2013en in UGC 11369, spanning from a phase near maximum light (t = + 1 d) to t = + 60 d with respect to the R-band maximum. Adopting a distance modulus of μ = 34.11 ± 0.15 mag and a total extinction (host galaxy+Milky Way) of AV ≈ 1.5 mag, we found that SN 2013en peaked at MR ≈ -18.6 mag, which is underluminous compared to the normal SNe Ia. The near maximum spectra show lines of Si II, Fe II, Fe III, Cr II, Ca II and other intermediate-mass and iron group elements which all have lower expansion velocities (i.e. ˜ 6000 km s- 1). The photometric and spectroscopic evolution of SN 2013en is remarkably similar to those of SN 2002cx and SN 2005hk, suggesting that they are likely to be generated from a similar progenitor scenario or explosion mechanism.

  4. A Study of the Type II-Plateau Supernova SN 2014cx

    NASA Astrophysics Data System (ADS)

    Flatland, Kelsi; Leonard, Douglas Christopher; Williams, George Grant; Smith, Paul S.; Bilinski, Christopher; Dessart, Luc; Gonzalez, Luis; Hoffman, Jennifer L.; Huk, Leah; Milne, Peter; Smith, Nathan

    2015-08-01

    The type II-plateau (II-P) class of supernova is the most commonly observed type of core-collapse event, and yet the basic characteristics of this class are still being defined (e.g. Pejcha & Prieto 2015). Here we add to the growing sample of type II-P events with well-sampled data from observations of SN 2014cx. SN 2014cx was independently discovered on September 2, 2014 UT by Nakano et al. (2014; CBET 3963) and Holoien et al. (2014; ATEL 6436) in the nearby (d ~ 20.7 Mpc, Tully 1988) SBd galaxy NGC 337. It was classified as a young Type II supernova through spectra taken within a day of discovery at both optical (Nakano et al. 2014) and near-infrared (Morrell et al. 2014; ATEL 6442) wavelengths. Later (Andrews et al. 2015; ATEL 7084), it was photometrically determined to be specifically a type II-P supernova, indicating the core-collapse event of a progenitor that had a large hydrogen envelope (Pejcha & Prieto 2015). We initiated a photometric and spectropolarimetric campaign to follow SN 2014cx; over a five month period following the supernova's discovery, we obtained optical images using the 1-meter telescope at Mount Laguna Observatory as part of the MOunt LAguna SUpernova Survey (MOLASUS), and spectra as part of the SuperNova SpectroPOLarimetry project (SNSPOL). Here we present the initial analysis of the photometry and spectroscopy obtained as part of this campaign. We acknowledge support from NSF grants AST-1009571 and AST-1210311, under which part of this research was carried out.

  5. A Study of the Type II-Plateau Supernova SN 2014cx

    NASA Astrophysics Data System (ADS)

    Flatland, Kelsi; Leonard, Douglas C.; Williams, Grant; Smith, Paul S.; Bilinski, Christopher; Gonzalez, Luis; Hoffman, Jennifer L.; Huk, Leah N.; Milne, Peter; Smith, Nathan; Supernova Spectropolarimetry Project

    2016-06-01

    The type II-plateau (II-P) class of supernova is the most commonly observed type of core-collapse event, and yet the basic characteristics of this class are still being defined (e.g. Pejcha & Prieto 2015). Here we add to the growing sample of type II-P events with well-sampled data from observations of SN 2014cx. SN 2014cx was independently discovered on September 2, 2014 UT by Nakano et al. (2014; CBET 3963) and Holoien et al. (2014; ATEL 6436) in the nearby (d ~ 20.7 Mpc, Tully 1988) SBd galaxy NGC 337. It was classified as a young Type II supernova through spectra taken within a day of discovery at both optical (Nakano et al. 2014) and near-infrared (Morrell et al. 2014; ATEL 6442) wavelengths. Later (Andrews et al. 2015; ATEL 7084), it was photometrically determined to be specifically a type II-P supernova, indicating the core-collapse event of a progenitor that had a large hydrogen envelope (Pejcha & Prieto 2015). We initiated a photometric and spectropolarimetric campaign to follow SN 2014cx; over a five month period following the supernova's discovery, we obtained optical images using the 1-meter telescope at Mount Laguna Observatory as part of the MOunt LAguna SUpernova Survey (MOLASUS), and spectra as part of the SuperNova SpectroPOLarimetry project (SNSPOL). Here we present the analysis of the photometry and spectroscopy obtained as part of this campaign. We acknowledge support from NSF grants AST-1009571 and AST-1210311, under which part of this research was carried out.

  6. AMI 15 GHz upper limits for the nearby Type Ia supernova SN 2016coj

    NASA Astrophysics Data System (ADS)

    Mooley, K. P.; Fender, R. P.; Cantwell, T.; Titterington, D.; Saunders, R.; Carey, S.; Hickish, J.; Perrott, Y. C.; Razavi-Ghods, N.; Scott, P.; Grainge, K.; Scaife, A.

    2016-06-01

    We observed the type Ia supernova SN 2016coj in NGC 4125 (Zheng et al., ATel #9095; d=19Mpc; discovery date 2016 May 28.18) with the AMI Large Array at 15 GHz. We detected a fading source (later found to be a chance coincidence; see below) at the location of the supernova on 2016 Jun 03.86, Jun 05.89 and Jun 09.76 UT, following which we triggered the Jansky VLA. The VLA observations, carried out between 2-18 GHz on Jun 11.07 UT, gave 3sigma upper limits of ~60 uJy at S, C, X and Ku bands.

  7. Nearby Supernova Factory Observations of SN 2006D: On SporadicCarbon Signatures in Early Type Ia Supernova Spectra

    SciTech Connect

    Thomas, R.C.; Aldering, G.; Antilogus, P.; Aragon, C.; Bailey,S.; Baltay, C.; Baron, E.; Bauer, A.; Buton, C.; Bongard, S.; Copin, Y.; Gangler, E.; Gilles, S.; Kessler, R.; Loken, S.; Nugent, P.; Pain, R.; Parrent, J.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigaudier, G.; Runge, K.; Scalzo, R.; Smadja, G.; Wang, L.; Weaver, B.A.

    2006-10-12

    We present four spectra of the Type Ia supernova SN Ia 2006Dextending from -7 to +13 days with respect to B-band maximum. The spectrainclude the strongest signature of unburned material at photosphericvelocities observed in a SN Ia to date. The earliest spectrum exhibits CII absorption features below 14,000 km/s, including a distinctive C IIlambda 6580 absorption feature. The carbon signatures dissipate as the SNapproaches peak brightness. In addition to discussing implications ofphotospheric-velocity carbon for white dwarf explosion models, we outlinesome factors that may influence the frequency of its detection before andaround peak brightness. Two effects are explored in this regard,including depopulation of the C II optical levels by non-LTE effects, andline-of-sight effects resulting from a clumpy distribution of unburnedmaterial with low volume-filling factor.

  8. ASAS-SN Discovery of A Probable Supernova in Unknown Redshift Galaxy 2MASX J0058421-1404122

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Koff, R. A.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Fernandez, J. M.; Masi, G.; Monard, L. A. G.; Nicholls, B.; Nicolas, J.

    2015-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the double 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J0058421-1404122.

  9. ASAS-SN Discovery of Two Probable Luminous Supernovae in Mrk 0283a and 2MASX J14021617+3339415

    NASA Astrophysics Data System (ADS)

    Masi, G.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Brimacombe, J.; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Fernandez, J. M.; Kiyota, S.; Nicholls, B.; Nicolas, J.

    2015-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered two luminous new transient sources, most likely supernovae, in the galaxies Mrk 0283a and 2MASX J14021617+3339415.

  10. Pac-Man in Space? ASAS-SN Discovery of A Probable Supernova in Galaxy Pair CGCG 314-006

    NASA Astrophysics Data System (ADS)

    Guo, Zhen; Holoien, T. W.-S.; Dong, Subo; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Chen, Ping; Brimacombe, J.

    2015-12-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the middle of the Pac-Man-shaped galaxy pair CGCG 314-006.

  11. X-ray emission from the historical supernovae in the spiral galaxy NGC 6946: SN 1980K and SN 1968D recovered ?

    NASA Technical Reports Server (NTRS)

    Schlegel, Eric M.

    1994-01-01

    This paper describes a study of the Roentgen Satellite (ROSAT) Position Sensitive Proportional Counter (PSPC) observation of the spiral galaxy NGC 6946 to search for x-ray emission from the six historical supernovae that have occurred in that galaxy. At the age of these supernovae, all could be emitting x rays due to circumstellar interactions. Supernova (SN) 1980K may be present based upon the hardness ratio and the coincidence of an x-ray source with the optical position. Its luminosity agrees with a recent prediction by Chevalier & Fransson. The situation for SN 1968D, apparently recovered in Very Large Array (VLA) data, is less clear due to source confusion, but suggests SN 1968D has not been recovered. Only upper limits are available for the remaining four supernovae that have occurred in this galaxy.

  12. Spectrophotometric time series of SN 2011fe from the Nearby Supernova Factory

    NASA Astrophysics Data System (ADS)

    Pereira, R.; Thomas, R. C.; Aldering, G.; Antilogus, P.; Baltay, C.; Benitez-Herrera, S.; Bongard, S.; Buton, C.; Canto, A.; Cellier-Holzem, F.; Chen, J.; Childress, M.; Chotard, N.; Copin, Y.; Fakhouri, H. K.; Fink, M.; Fouchez, D.; Gangler, E.; Guy, J.; Hillebrandt, W.; Hsiao, E. Y.; Kerschhaggl, M.; Kowalski, M.; Kromer, M.; Nordin, J.; Nugent, P.; Paech, K.; Pain, R.; Pécontal, E.; Perlmutter, S.; Rabinowitz, D.; Rigault, M.; Runge, K.; Saunders, C.; Smadja, G.; Tao, C.; Taubenberger, S.; Tilquin, A.; Wu, C.

    2013-06-01

    We present 32 epochs of optical (3300-9700 Å) spectrophotometric observations of the nearby quintessential "normal" type Ia supernova (SN Ia) SN 2011fe in the galaxy M101, extending from -15 to +97 d with respect to B-band maximum, obtained by the Nearby Supernova Factory collaboration. SN 2011fe is the closest (μ = 29.04) and brightest (Bmax = 9.94 mag) SN Ia observed since the advent of modern large scale programs for the intensive periodic followup of supernovae. Both synthetic light curve measurements and spectral feature analysis attest to the normality of SN 2011fe. There is very little evidence for reddening in its host galaxy. The homogeneous calibration, intensive time sampling, and high signal-to-noise ratio of the data set make it unique. Thus it is ideal for studying the physics of SN Ia explosions in detail, and for furthering the use of SNe Ia as standardizable candles for cosmology. Several such applications are shown, from the creation of a bolometric light curve and measurement of the 56Ni mass, to the simulation ofdetection thresholds for unburned carbon, direct comparisons with other SNe Ia, and existing spectral templates. A movie is available in electronic form at http://www.aanda.orgAll the reduced spectra are available as FITS files in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5">130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/554/A27

  13. TYCHO SN 1572: A NAKED Ia SUPERNOVA REMNANT WITHOUT AN ASSOCIATED AMBIENT MOLECULAR CLOUD

    SciTech Connect

    Tian, W. W.; Leahy, D. A.

    2011-03-10

    The historical supernova remnant (SNR) Tycho SN 1572 originates from the explosion of a normal Type Ia supernova that is believed to have originated from a carbon-oxygen white dwarf in a binary system. We analyze the 21 cm continuum, H I, and {sup 12}CO-line data from the Canadian Galactic Plane Survey in the direction of SN 1572 and the surrounding region. We construct H I absorption spectra to SN 1572 and three nearby compact sources. We conclude that SN 1572 has no molecular cloud interaction, which argues against previous claims that a molecular cloud is interacting with the SNR. This new result does not support a recent claim that dust, newly detected by AKARI, originates from such an SNR-cloud interaction. We suggest that the SNR has a kinematic distance of 2.5-3.0 kpc based on a nonlinear rotational curve model. Very high energy {gamma}-ray emission from the remnant has been detected by the VERITAS telescope, so our result shows that its origin should not be an SNR-cloud interaction. Both radio and X-ray observations support that SN 1572 is an isolated Type Ia SNR.

  14. Tycho SN 1572: A Naked Ia Supernova Remnant Without an Associated Ambient Molecular Cloud

    NASA Astrophysics Data System (ADS)

    Tian, W. W.; Leahy, D. A.

    2011-03-01

    The historical supernova remnant (SNR) Tycho SN 1572 originates from the explosion of a normal Type Ia supernova that is believed to have originated from a carbon-oxygen white dwarf in a binary system. We analyze the 21 cm continuum, H I, and 12CO-line data from the Canadian Galactic Plane Survey in the direction of SN 1572 and the surrounding region. We construct H I absorption spectra to SN 1572 and three nearby compact sources. We conclude that SN 1572 has no molecular cloud interaction, which argues against previous claims that a molecular cloud is interacting with the SNR. This new result does not support a recent claim that dust, newly detected by AKARI, originates from such an SNR-cloud interaction. We suggest that the SNR has a kinematic distance of 2.5-3.0 kpc based on a nonlinear rotational curve model. Very high energy γ-ray emission from the remnant has been detected by the VERITAS telescope, so our result shows that its origin should not be an SNR-cloud interaction. Both radio and X-ray observations support that SN 1572 is an isolated Type Ia SNR.

  15. Hubble space telescope and ground-based observations of the type Iax supernovae SN 2005hk and SN 2008A

    SciTech Connect

    McCully, Curtis; Jha, Saurabh W.; Foley, Ryan J.; Chornock, Ryan; Holtzman, Jon A.; Balam, David D.; Branch, David; Filippenko, Alexei V.; Ganeshalingam, Mohan; Li, Weidong; Frieman, Joshua; Fynbo, Johan; Leloudas, Giorgos; Galbany, Lluis; Garnavich, Peter M.; Graham, Melissa L.; Hsiao, Eric Y.; Leonard, Douglas C.; and others

    2014-05-10

    We present Hubble Space Telescope (HST) and ground-based optical and near-infrared observations of SN 2005hk and SN 2008A, typical members of the Type Iax class of supernovae (SNe). Here we focus on late-time observations, where these objects deviate most dramatically from all other SN types. Instead of the dominant nebular emission lines that are observed in other SNe at late phases, spectra of SNe 2005hk and 2008A show lines of Fe II, Ca II, and Fe I more than a year past maximum light, along with narrow [Fe II] and [Ca II] emission. We use spectral features to constrain the temperature and density of the ejecta, and find high densities at late times, with n{sub e} ≳ 10{sup 9} cm{sup –3}. Such high densities should yield enhanced cooling of the ejecta, making these objects good candidates to observe the expected 'infrared catastrophe', a generic feature of SN Ia models. However, our HST photometry of SN 2008A does not match the predictions of an infrared catastrophe. Moreover, our HST observations rule out a 'complete deflagration' that fully disrupts the white dwarf for these peculiar SNe, showing no evidence for unburned material at late times. Deflagration explosion models that leave behind a bound remnant can match some of the observed properties of SNe Iax, but no published model is consistent with all of our observations of SNe 2005hk and 2008A.

  16. Determination of RV and Distance for SN 2012cu, the Type Ia Supernova with Highest Extinction

    NASA Astrophysics Data System (ADS)

    Huang, Xiaosheng; Raha, Zachary; Aldering, Greg Scott; Antilogus, Pierre; Aragon, Cecilia; Bailey, Stephen J.; Baltay, Charles; Barbary, Kyle H.; Baugh, Derek; Boone, Kyle; Bongard, Sebastien; Buton, Clement; Chen, Juncheng; Childress, Michael; Chotard, Nicolas; Copin, Yannick; Fagrelius, Parker; Fakhouri, Hannah; Feindt, Ulrich; Fleury, Mathilde; Fouchez, Dominique; Gangler, Emmanuel; Hayden, Brian; Kim, Alex G.; Kowalski, Marek; Leget, Pierre-Francois; Lombardo, Simona; Nordin, Jakob; Pain, Reynald; Pecontal, Emmanuel; Pereira, Rui; Perlmutter, Saul; Rabinowitz, David L.; Rigault, Mickael; Rubin, David; Runge, Karl; Saunders, Clare; Scalzo, Richard A.; Smadja, Gerard; Sofiatti, Caroline; Suzuki, Nao; Stocker, Andrew; Taubenberger, Stefan; Tao, Charling; Thomas, Rollin; Nearby Supernova Factory

    2016-01-01

    Multi-epoch, flux-calibrated spectroscopic data of a highly reddened Type Ia supernova, SN2012cu, from 3300 - 9700 Å, were obtained using the SuperNova Integrated Field Spectrograph. We determine its best-fit color excess, E(B-V), and total-to-selective extinction ratio, RV. We detect in the near-maximum spectra two of the diffuse interstellar band features and we further find the dust extinction properties toward SN2012cu in its host to be like those of the Milky Way. We also compare the reddening laws of Cardelli et al. (1989), O'Donnell (1994), and Fitzpatrick (1999), and find the predictions of the latter fit the data the best. Finally, the distance to the host galaxy, NGC4772, is determined to within 6%. We compare our result with distance measurements based on the Tully-Fisher method in the literature.

  17. Spectra of two very old supernovae - SN 1986J and SN 1980K

    NASA Technical Reports Server (NTRS)

    Leibundgut, Bruno; Kirshner, Robert P.; Pinto, Philip A.; Rupen, Michael P.; Smith, R. Chris

    1991-01-01

    Spectra are presented for SN 1986J in NGC 891, observed 4 and 7 years after the explosion, and SN 1980K, observed 9 years after maximum light. A narrow-line and a broad-line component are noted in SN 1986J; these are respectively attributed to a circumstellar shell and the actual stellar interior (without hydrogen). SN 1980K continues to emit in very broad lines. Comparison with earlier observations suggests that this SN halted its exponential flux decline in the early 1980s, and is currently emitting at a constant rate. In both SNs studies, the identity of the energy source which sustains emission remains uncertain.

  18. Spectroscopic Classification of SN 2016aqw as a Young Type II Supernova

    NASA Astrophysics Data System (ADS)

    Zhang, Jujia; Wang, Chuanjun; Wang, Xiaofeng

    2016-03-01

    We report an optical spectrum (range 340-900 nm) of SN 2016aqw that was obtained on UT Mar.03.86 2016 with the 2.4-m telescope (+YFOSC) at LiJiang Gaomeigu Station of Yunnan Astronomical Observatories (YNAO). The spectrum is characterized by the Ha peak that is superimposed on a very blue continuum, consistent with that of a young type II supernova.

  19. Scattered-Light Echoes from the Historical Galactic Supernovae Cassiopeia A and Tycho (SN 1572)

    SciTech Connect

    Rest, A; Welch, D L; Suntzeff, N B; Oaster, L; Lanning, H; Olsen, K; Smith, R C; Becker, A C; Bergmann, M; Challis, P; Clocchiatti, A; Cook, K H; Damke, G; Garg, A; Huber, M E; Matheson, T; Minniti, D; Prieto, J L; Wood-Vasey, W M

    2008-05-06

    We report the discovery of an extensive system of scattered light echo arclets associated with the recent supernovae in the local neighborhood of the Milky Way: Tycho (SN 1572) and Cassiopeia A. Existing work suggests that the Tycho SN was a thermonuclear explosion while the Cas A supernova was a core collapse explosion. Precise classifications according to modern nomenclature require spectra of the outburst light. In the case of ancient SNe, this can only be done with spectroscopy of their light echo, where the discovery of the light echoes from the outburst light is the first step. Adjacent light echo positions suggest that Cas A and Tycho may share common scattering dust structures. If so, it is possible to measure precise distances between historical Galactic supernovae. On-going surveys that alert on the development of bright scattered-light echo features have the potential to reveal detailed spectroscopic information for many recent Galactic supernovae, both directly visible and obscured by dust in the Galactic plane.

  20. Optical and NIR observations of the nearby type Ia supernova SN 2014J

    NASA Astrophysics Data System (ADS)

    Srivastav, Shubham; Ninan, J. P.; Kumar, B.; Anupama, G. C.; Sahu, D. K.; Ojha, D. K.; Prabhu, T. P.

    2016-03-01

    Optical and NIR observations of the Type Ia supernova SN 2014J in M82 are presented. The observed light curves are found to be similar to normal Type Ia supernovae (SNe Ia), with a decline rate parameter Δm15(B) = 1.08 ± 0.03. The supernova reached B-band maximum on JD 2456690.14, at an apparent magnitude mB(max) = 11.94. The optical spectra show a red continuum with deep interstellar Na I absorption, but otherwise resemble those of normal SNe Ia. The Si II λ6355 feature indicates a velocity of ˜12 000 km s-1 at B-band maximum, which places SN 2014J at the border of the normal velocity and high velocity group of SNe Ia. The velocity evolution of SN 2014J places it in the Low Velocity Gradient subclass, whereas the equivalent widths of Si II features near B-band maximum place it at the border of the core normal and Broad Line subclasses of SNe Ia. An analytic model fit to the bolometric light curve indicates that a total of ˜1.3 M⊙ was ejected in the explosion, and the ejected 56Ni mass MNi ˜ 0.6 M⊙. The low [Fe III] λ4701 to [Fe II] λ5200 ratio in the nebular spectra of SN 2014J hints towards clumpiness in the ejecta. Optical broad-band, linear polarimetric observations of SN 2014J obtained on four epochs indicate an almost constant polarization (PR ˜2.7 per cent; θ ˜ 37°), which suggests that the polarization signal is of interstellar origin.

  1. Regularly pulsed neutrinos from supernova SN1987A?

    NASA Technical Reports Server (NTRS)

    Harwit, Martin; Wasserman, Ira M.; Biermann, Peter L.; Meyer, Hinrich

    1987-01-01

    Some consequences of the 8.9 millisecond periodicity observed in neutrino events from SN1987A with the Kamiokonde and IMB experiments are discussed. Interpreting the apparent period as a rotation of a compact object would imply that the neutrino emission is anisotropic and that the neutrino mass, averaged over all observed flavors, is less than 0.2 eV/c-squared. It is also noted that P = 8.9 ms is a reasonable period for very young pulsars.

  2. Preliminary NIR Late Light Curve of the Type Ia Supernova SN2009nr

    NASA Astrophysics Data System (ADS)

    Heath, Jonathan; Bryngelson, G.

    2013-01-01

    Type Ia supernovae (SNe Ia) are important in determining the expansion of the universe based on the uniformity of their light curves. It is essential to understand the behavior of these supernovae in order to strengthen our confidence in their use as standard candles. A small, but increasing number of SNe Ia have been observed later than the 200 day epoch in the near-infrared (NIR). Most of these exhibit a flattening of the NIR power, even as the visible light declines at a steady rate. It is unclear as to exactly what causes this behavior, and how typical it is. In order to characterize the late behavior of SNe Ia, images of the supernova SN2009nr were analyzed using the Image Reduction and Analysis Facility (IRAF). These images were taken with the 4m Mayall Telescope at Kitt Peak National-Observatory using the FLAMINGOS IR Imaging Spectrometer. The supernova’s magnitude was normalized with respect to the magnitudes of known stars so that traits related to the supernova may be compared to others. We present preliminary NIR (J, H, K) light curves of the observed supernova and compare them to other SNe Ia observed at these epochs.

  3. Explaining the Most Energetic Supernovae with an Inefficient Jet-feedback Mechanism

    NASA Astrophysics Data System (ADS)

    Gilkis, Avishai; Soker, Noam; Papish, Oded

    2016-08-01

    We suggest that the energetic radiation from core-collapse super-energetic supernovae (SESNe) is due to a long-lasting accretion process onto the newly born neutron star (NS), resulting from an inefficient operation of the jet-feedback mechanism (JFM). The jets that are launched by the accreting NS or black hole maintain their axis due to a rapidly rotating pre-collapse core and do not manage to eject core material from near the equatorial plane. The jets are able to eject material from the core along the polar directions and reduce the gravity near the equatorial plane. The equatorial gas expands, and part of it falls back over a timescale of minutes to days to prolong the jet-launching episode. According to the model for SESNe proposed in the present paper, the principal parameter that distinguishes between the different cases of core-collapse supernova (CCSN) explosions, such as between normal CCSNe and SESNe, is the efficiency of the JFM. This efficiency, in turn, depends on the pre-collapse core mass, envelope mass, core convection, and, most of all, the angular momentum profile in the core. One prediction of the inefficient JFM for SESNe is the formation of a slow equatorial outflow in the explosion. The typical velocity and mass of this outflow are estimated to be v eq ≈ 1000 km s‑1 and M eq ≳ 1 M ⊙, respectively, though quantitative values will have to be checked in future hydrodynamic simulations.

  4. Supernovae. ⁴⁴Ti gamma-ray emission lines from SN1987A reveal an asymmetric explosion.

    PubMed

    Boggs, S E; Harrison, F A; Miyasaka, H; Grefenstette, B W; Zoglauer, A; Fryer, C L; Reynolds, S P; Alexander, D M; An, H; Barret, D; Christensen, F E; Craig, W W; Forster, K; Giommi, P; Hailey, C J; Hornstrup, A; Kitaguchi, T; Koglin, J E; Madsen, K K; Mao, P H; Mori, K; Perri, M; Pivovaroff, M J; Puccetti, S; Rana, V; Stern, D; Westergaard, N J; Zhang, W W

    2015-05-01

    In core-collapse supernovae, titanium-44 ((44)Ti) is produced in the innermost ejecta, in the layer of material directly on top of the newly formed compact object. As such, it provides a direct probe of the supernova engine. Observations of supernova 1987A (SN1987A) have resolved the 67.87- and 78.32-kilo-electron volt emission lines from decay of (44)Ti produced in the supernova explosion. These lines are narrow and redshifted with a Doppler velocity of ~700 kilometers per second, direct evidence of large-scale asymmetry in the explosion. PMID:25954004

  5. High-velocity emission in young supernova remnants: SN 1006 and SN 1572

    NASA Technical Reports Server (NTRS)

    Kirshner, Robert; Winkler, P. Frank; Chevalier, Roger A.

    1987-01-01

    The paper reports the discovery of broad H-alpha emission from the SN 1006 remnant with a FWHM velocity of 2600 + or - 100 km/s. This emission is similar to that seen in the remnant of SN 1572 which has a FWHM for H-alpha of 1800 km/s. The nonradiative model was used to interpret the line widths and the derived shock velocity was compared with proper motion measurements to derive distances of 1.4-2.1 kpc to SN 1006 and 2.0-2.8 kpc to SN 1572.

  6. High-velocity emission in young supernova remnants: SN 1006 and SN 1572

    SciTech Connect

    Kirshner, R.; Winkler, P.F.; Chevalier, R.A.

    1987-04-01

    The paper reports the discovery of broad H-alpha emission from the SN 1006 remnant with a FWHM velocity of 2600 + or - 100 km/s. This emission is similar to that seen in the remnant of SN 1572 which has a FWHM for H-alpha of 1800 km/s. The nonradiative model was used to interpret the line widths and the derived shock velocity was compared with proper motion measurements to derive distances of 1.4-2.1 kpc to SN 1006 and 2.0-2.8 kpc to SN 1572. 24 references.

  7. Core collapse supernovae from blue supergiant progenitors : The evolutionary history of SN 1987A

    NASA Astrophysics Data System (ADS)

    Menon, Athira

    2015-08-01

    SN 1987A is historically one of the most remarkable supernova explosions to be seen from Earth. Due to the proximity of its location in the LMC, it remains the most well-studied object outside the solar system. It was also the only supernova whose progenitor was observed prior to its explosion.SN 1987A however, was a unique and enigmatic core collapse supernova. It was the first Type II supernova to have been observed to have exploded while its progenitor was a blue supergiant (BSG). Until then Type II supernovae were expected to originate from explosions of red supergiants (RSGs). A spectacular triple-ring nebula structure, rich in helium and nitrogen, was observed around the remnant, indicating a recent RSG phase before becoming a BSG. Even today it is not entirely understood what the evolutionary history may have been to cause a BSG to explode. The most commonly accepted hypothesis for its origin is the merger of a massive binary star system.An evolutionary scenario for such a binary system, was proposed by Podsiadlowski (1992) (P92). Through SPH simulations of the merger and the stellar evolution of the post-merger remnant, Ivanova & Podsiadlowski (2002) and (2003) (I&M) could successfully obtain the RSG to BSG transition of the progenitor.The aim of the present work is to produce the evolutionary history of the progenitor of SN 1987A and its explosion. We construct our models based on the results of P92 and I&M. Here, the secondary (less massive) star is accreted on the primary, while being simultaneously mixed in its envelope over a period of 100 years. The merged star is evolved until the onset of core collapse. For this work we use the 1-dimensional, implicit, hydrodynamical stellar evolution code, KEPLER. A large parameter space is explored, consisting of primary (16-20 Ms) and secondary masses (5-8 Ms), mixing boundaries, and accreting timescales. Those models whose end states match the observed properties of the progenitor of SN 1987A are exploded. The

  8. The Unusual Super-luminous Supernovae SN 2011kl and ASASSN-15lh

    NASA Astrophysics Data System (ADS)

    Bersten, Melina C.; Benvenuto, Omar G.; Orellana, Mariana; Nomoto, Ken'ichi

    2016-01-01

    Two recently discovered very luminous supernovae (SNe) present stimulating cases to explore the extents of the available theoretical models. SN 2011kl represents the first detection of a supernova explosion associated with an ultra-long duration gamma-ray burst. ASASSN-15lh was even claimed as the most luminous SN ever discovered, challenging the scenarios so far proposed for stellar explosions. Here we use our radiation hydrodynamics code in order to simulate magnetar-powered SNe. To avoid explicitly assuming neutron star properties, we adopt the magnetar luminosity and spin-down timescale as free parameters of the model. We find that the light curve (LC) of SN 2011kl is consistent with a magnetar power source, as previously proposed, but we note that some amount of 56Ni (≳ 0.08{M}⊙ ) is necessary to explain the low contrast between the LC peak and tail. For the case of ASASSN-15lh, we find physically plausible magnetar parameters that reproduce the overall shape of the LC provided the progenitor mass is relatively large (an ejecta mass of ≈ 6{M}⊙ ). The ejecta hydrodynamics of this event is dominated by the magnetar input, while the effect is more moderate for SN 2011kl. We conclude that a magnetar model may be used for the interpretation of these events and that the hydrodynamical modeling is necessary to derive the properties of powerful magnetars and their progenitors.

  9. SN 1984A and Delayed Detonation Models of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Lentz, E. J.; Baron, E.; Branch, D.; Hauschildt, P. H.

    1999-12-01

    Supernova SN 1984A shows unusually large expansion velocities in lines from freshly synthesized material, relative to typical Type Ia supernovae (SNe Ia). SN 1984A represents an extreme example of SNe Ia with large expansion velocities, but otherwise normal spectra. We have modeled several early spectra of SN 1984A with the multi-purpose NLTE model atmosphere and spectrum synthesis code, PHOENIX. We have used as input two delayed detonation models, DD21c (Höflich et al. 1998) and CS15DD3 (Iwamoto et al. 1999). These models show line expansion velocities which are larger than for typical deflagration models like W7 (Nomoto et al. 1984, Thielemann et al. 1986), which we have previously shown to fit normal SNe Ia quite well (Lentz et al. 2000). Higher densities of newly synthesized material from burning at higher velocities are found in delayed detonation models than in deflagration models. We find these delayed detonation models to be reasonable approximations to high expansion velocity SNe Ia like SN 1984A. Even if the explosion mechanism of the delayed detonation models is incorrect, the density of synthesized material at high velocities is of the right magnitude.

  10. SN1987A: The Birth of a Supernova Remnant

    NASA Technical Reports Server (NTRS)

    McCray, Richard

    2003-01-01

    This grant was intended to support the development of theoretical models needed to interpret and understand the observations by the Hubble Space Telescope and the Chandra X-ray telescope of the rapidly developing remnant of Supernova 1987A. In addition, we carried out a few investigations of related topics. The project was spectacularly successful. The models that we developed provide the definitive framework for predicting and interpreting this phenomenon. Following is a list of publications based on our work. Some of these papers include results of both theoretical modeling supported by this project and also analysis of data supported by the Space Telescope Science Institute and the Chandra X-ray Observatory. We first list papers published in refereed journals, then conference proceedings and book chapters, and also an educational web site.

  11. Radio structure of the remnant of Tycho's supernova (SN 1572)

    NASA Technical Reports Server (NTRS)

    Dickel, J. R.; Van Breugel, W. J. M.; Strom, R. G.

    1991-01-01

    The radio emission from the remnant of Tycho's supernova of 1572 arises in a nearly circular, clumpy shell. A very distinct, thin bright rim just outside the main shell can be seen around most of the periphery of the remnant. The outer edge of radio emission, usually defined by this bright rim, coincides perfectly with the outer X-ray boundary. Most of the emission is polarized by a modest amount, with the outer rim particularly prominent. Observations at several wavelengths are used to map out the rotation measure at high angular resolution, and determine the intrinsic magnetic field direction. The magnetic field shows a somewhat cellular pattern but with a net radial orientation and a generally fairly low degree of polarization.

  12. Radio structure of the remnant of Tycho's supernova (SN 1572)

    SciTech Connect

    Dickel, J.R.; Van breugel, W.J.M.; Strom, R.G. Lawrence Livermore National Laboratory, Livermore, CA Netherlands Foundation for Research in Astronomy, Dwingeloo )

    1991-06-01

    The radio emission from the remnant of Tycho's supernova of 1572 arises in a nearly circular, clumpy shell. A very distinct, thin bright rim just outside the main shell can be seen around most of the periphery of the remnant. The outer edge of radio emission, usually defined by this bright rim, coincides perfectly with the outer X-ray boundary. Most of the emission is polarized by a modest amount, with the outer rim particularly prominent. Observations at several wavelengths are used to map out the rotation measure at high angular resolution, and determine the intrinsic magnetic field direction. The magnetic field shows a somewhat cellular pattern but with a net radial orientation and a generally fairly low degree of polarization. 44 refs.

  13. The Crab nebula and the class of Type IIn-P supernovae caused by sub-energetic electron-capture explosions

    NASA Astrophysics Data System (ADS)

    Smith, Nathan

    2013-09-01

    What sort of supernova (SN) gave rise to the Crab nebula? While there are several indications that the Crab arose from a sub-energetic explosion of an 8-10 M⊙ progenitor star, this would appear to conflict with the high luminosity indicated by historical observations. This paper shows that several well-known observed properties of the Crab and SN 1054 are well matched by a particular breed of Type IIn SN. The Crab's properties are best suited to the Type IIn-P subclass (Type IIn spectra with plateau light curves), exemplified by SNe 1994W, 2009kn and 2011ht. These events probably arise from relatively low energy (1050 erg) explosions with low 56Ni yield that may result from electron-capture SN (ecSN) explosions, but their high visual-wavelength luminosity and Type IIn spectra are dominated by shock interaction with dense circumstellar material (CSM) rather than the usual recombination photosphere. In this interaction, a large fraction of the 1050 erg of the total kinetic energy can be converted to visual-wavelength luminosity. After about 120 d, nearly all of the mass outside the neutron star in the CSM and ejecta ends up in a slowly expanding (1000-1500 km s-1) thin dense shell, which is then accelerated and fragmented by the growing pulsar wind nebula in the subsequent 1000 yr, producing the complex network of filaments seen today. There is no need to invoke the extended, invisible fast SN envelope hypothesized to reside outside the Crab. As differentiated from a normal SN II-P, SNe IIn-P provide a much better explanation for several observed features of the Crab: (1) no blast wave outside the Crab nebula filaments, (2) no rapidly expanding SN envelope outside the filaments, (3) a total mass of ˜5 M⊙ swept up in a thin slow shell, (4) a low kinetic energy of the Crab at least an order of magnitude below a normal core-collapse SN, (5) a high peak luminosity (-18 mag) despite the low kinetic energy, (6) chemical abundances consistent with an 8-10 M⊙ star and

  14. Detection of a very bright source close to the LMC supernova SN 1987A

    NASA Technical Reports Server (NTRS)

    Nisenson, P.; Papaliolios, C.; Karovska, M.; Noyes, R.

    1987-01-01

    High angular resolution observations of the supernova in the Large Magellanic Cloud, SN 1987A, have revealed a bright source separated from the SN by approximately 60 mas with a magnitude difference of 2.7 at 656 nm (H-alpha). Speckle imaging techniques were applied to data recorded with the CfA two-dimensional photon counting detector on the CTIO 4 m telescope on March 25 and April 2 to allow measurements in H-alpha on both nights and at 533 nm and 450 nm on the second night. The nature of this object is as yet unknown, though it is almost certainly a phenomenon related to the SN.

  15. Constraining the progenitor of the Type Ia Supernova SN 2012cg

    NASA Astrophysics Data System (ADS)

    Liu, Zheng-Wei; Stancliffe, Richard J.

    2016-06-01

    The nature of the progenitors of Type Ia supernovae (SNe Ia) is not yet fully understood. In the single-degenerate (SD) scenario, the collision of the SN ejecta with its companion star is expected to produce detectable ultraviolet emission in the first few days after the SN explosion within certain viewing angles. It was recently found that the B - V colour of the nearby SN Ia SN 2012cg at about 16 d before the maximum B-band brightness was about 0.2 mag bluer than those of other normal SNe Ia, which was reported as the first evidence for excess blue light from the interaction of normal SN Ia ejecta with its companion star. In this work, we compare current observations for SN 2012cg from its pre-explosion phase to the late-time nebular phase with theoretical predictions from binary evolution and population synthesis calculations for a variety of popular progenitor scenarios. We find that a main-sequence donor or a carbon-oxygen white dwarf donor binary system is more likely to be the progenitor of SN 2012cg. However, both scenarios also predict properties which are in contradiction to the observed features of this system. Taking both theoretical and observational uncertainties into account, we suggest that it might be too early to conclude that SN 2012cg was produced from an explosion of a Chandrasekhar-mass white dwarf in the SD scenario. Future observations and improved detailed theoretical modelling are still required to place a more stringent constraint on the progenitor of SN 2012cg.

  16. SN 2012im/2013ek: A Supernova Double Take in NGC 6984

    NASA Astrophysics Data System (ADS)

    Milisavljevic, Dan

    2013-10-01

    An unprecedented transient event has just been detected in a spiral arm of NGC 6984. Two H-poor supernovae - SN 2012im and 2013ek - both originating from massive stripped-envelope progenitor stars have been found at virtually the same location {< 0.4 arcsec}. Interpretations have varied widely. Chance alignment of two completely independent supernovae of the same Type Ib/c class exploding within one year of each other from the same stellar cluster is statistically improbable. Thus, the two explosions are most likely physically related, and this has important ramifications in areas of high-mass binary star evolution and explosion mechanisms of core-collapse supernovae.High resolution HST images are the only means by which to probe the stellar environment of the progenitor system. To this end, we request WFC3/UVIS imaging in F336W, F475W, F555W, and F814W of SN 2013ek in the next month while SN 2013ek is still bright to pin down its precise location within a nearby cluster of stars visible in an archival plate of NGC 6984. Complementary follow-up images will be requested during regular GO proposals in Cycle 22 when the fading supernova reveals what is left behind. The proposed suite of images will allow us to model the cluster's broadband colors to determine properties of the progenitor star system's environment {e.g., mass, age, luminosity, star formation rate, metallicity} that will be used to constrain possible explosion scenarios.We request Director's Discretionary time for these observations as a non-disruptive TOO.

  17. SN 2015U: a rapidly evolving and luminous Type Ibn supernova

    NASA Astrophysics Data System (ADS)

    Shivvers, Isaac; Zheng, Wei Kang; Mauerhan, Jon; Kleiser, Io K. W.; Van Dyk, Schuyler D.; Silverman, Jeffrey M.; Graham, Melissa L.; Kelly, Patrick L.; Filippenko, Alexei V.; Kumar, Sahana

    2016-09-01

    Supernova (SN) 2015U (also known as PSN J07285387+3349106) was discovered in NGC 2388 on 2015 Feb. 11. A rapidly evolving and luminous event, it showed effectively hydrogen-free spectra dominated by relatively narrow helium P-Cygni spectral features and it was classified as an SN Ibn. In this paper, we present photometric, spectroscopic, and spectropolarimetric observations of SN 2015U, including a Keck/DEIMOS spectrum (resolution ≈5000) which fully resolves the optical emission and absorption features. We find that SN 2015U is best understood via models of shock breakout from extended and dense circumstellar material (CSM), likely created by a history of mass-loss from the progenitor with an extreme outburst within ˜1-2 yr of core collapse (but we do not detect any outburst in our archival imaging of NGC 2388). We argue that the high luminosity of SN 2015U was powered not through 56Ni decay but via the deposition of kinetic energy into the ejecta/CSM shock interface. Though our analysis is hampered by strong host-galaxy dust obscuration (which likely exhibits multiple components), our data set makes SN 2015U one of the best-studied Type Ibn SNe and provides a bridge of understanding to other rapidly fading transients, both luminous and relatively faint.

  18. SN 2013ab: a normal Type IIP supernova in NGC 5669

    NASA Astrophysics Data System (ADS)

    Bose, Subhash; Valenti, Stefano; Misra, Kuntal; Pumo, Maria Letizia; Zampieri, Luca; Sand, David; Kumar, Brijesh; Pastorello, Andrea; Sutaria, Firoza; Maccarone, Thomas J.; Kumar, Brajesh; Graham, M. L.; Howell, D. Andrew; Ochner, Paolo; Chandola, H. C.; Pandey, Shashi B.

    2015-07-01

    We present densely sampled ultraviolet/optical photometric and low-resolution optical spectroscopic observations of the Type IIP supernova 2013ab in the nearby (˜24 Mpc) galaxy NGC 5669, from 2 to 190 d after explosion. Continuous photometric observations, with the cadence of typically a day to one week, were acquired with the 1-2 m class telescopes in the Las Cumbres Observatory Global Telescope network, ARIES telescopes in India and various other telescopes around the globe. The light curve and spectra suggest that the supernova (SN) is a normal Type IIP event with a plateau duration of ˜80 d with mid-plateau absolute visual magnitude of -16.7, although with a steeper decline during the plateau (0.92 mag 100 d-1 in V band) relative to other archetypal SNe of similar brightness. The velocity profile of SN 2013ab shows striking resemblance with those of SNe 1999em and 2012aw. Following the Rabinak & Waxman prescription, the initial temperature evolution of the SN emission allows us to estimate the progenitor radius to be ˜800 R⊙, indicating that the SN originated from a red supergiant star. The distance to the SN host galaxy is estimated to be 24.3 Mpc from expanding photosphere method. From our observations, we estimate that 0.064 M⊙ of 56Ni was synthesized in the explosion. General relativistic, radiation hydrodynamical modelling of the SN infers an explosion energy of 0.35 × 1051 erg, a progenitor mass (at the time of explosion) of ˜9 M⊙ and an initial radius of ˜600 R⊙.

  19. INVERSE COMPTON X-RAY EMISSION FROM SUPERNOVAE WITH COMPACT PROGENITORS: APPLICATION TO SN2011fe

    SciTech Connect

    Margutti, R.; Soderberg, A. M.; Chomiuk, L.; Milisavljevic, D.; Foley, R. J.; Slane, P.; Moe, M.; Chevalier, R.; Hurley, K.; Hughes, J. P.; Fransson, C.; Barthelmy, S.; Cummings, J.; Briggs, M.; Connaughton, V.; Costa, E.; Del Monte, E. [INAF and others

    2012-06-01

    We present a generalized analytic formalism for the inverse Compton X-ray emission from hydrogen-poor supernovae and apply this framework to SN 2011fe using Swift X-Ray Telescope (XRT), UVOT, and Chandra observations. We characterize the optical properties of SN 2011fe in the Swift bands and find them to be broadly consistent with a 'normal' SN Ia, however, no X-ray source is detected by either XRT or Chandra. We constrain the progenitor system mass-loss rate M-dot < 2 x 10{sup -9} M{sub Sun }yr{sup -1} (3{sigma} c.l.) for wind velocity v{sub w} = 100 km s{sup -1}. Our result rules out symbiotic binary progenitors for SN 2011fe and argues against Roche lobe overflowing subgiants and main-sequence secondary stars if {approx}> 1% of the transferred mass is lost at the Lagrangian points. Regardless of the density profile, the X-ray non-detections are suggestive of a clean environment (n{sub CSM} < 150 cm{sup -3}) for 2 Multiplication-Sign 10{sup 15} {approx}< R {approx}< 5 Multiplication-Sign 10{sup 16} cm around the progenitor site. This is either consistent with the bulk of material being confined within the binary system or with a significant delay between mass loss and supernova explosion. We furthermore combine X-ray and radio limits from Chomiuk et al. to constrain the post-shock energy density in magnetic fields. Finally, we searched for the shock breakout pulse using gamma-ray observations from the Interplanetary Network and find no compelling evidence for a supernova-associated burst. Based on the compact radius of the progenitor star we estimate that the shock breakout pulse was likely not detectable by current satellites.

  20. Supernovae

    NASA Astrophysics Data System (ADS)

    March, Marisa

    2014-03-01

    We live in a Universe that is getting bigger faster. This astonishing discovery of Universal acceleration was made in the late 1990s by two teams who made observations of a special type of exploded star known as a `Supernova Type Ia'. (SNeIa) Since the discovery of the accelerating Universe, one of the biggest questions in modern cosmology has been to determine the cause of that acceleration - the answer to this question will have far reaching implications for our theories of cosmology and fundamental physics more broadly. The two main competing explanations for this apparent late time acceleration of the Universe are modified gravity and dark energy. The Dark Energy Survey (DES) has been designed and commissioned to find to find answers to these questions about the nature of dark energy and modified gravity. The new 570 megapixel Dark Energy Camera is currently operating with the Cerro-Tololo Inter American Observatory's 4m Blanco teleccope, carrying out a systematic search for SNeIa, and mapping out the large scale structure of the Universe by making observations of galaxies. The DES science program program which saw first light in September 2013 will run for five years in total. DES SNeIa data in combination with the other DES observations of large scale structure will enable us to put increasingly accurate constraints on the expansion history of the Universe and will help us distinguish between competing theories of dark energy and modified gravity. As we draw to the close of the first observing season of DES in March 2014, we will report on the current status of the DES supernova survey, presenting first year supernovae data, preliminary results, survey strategy, discovery pipeline, spectroscopic target selection and data quality. This talk will give the first glimpse of the DES SN first year data and initial results as we begin our five year survey in search of dark energy. On behalf of the Dark Energy Survey collaboration.

  1. Supernova SN 2011fe from an exploding carbon-oxygen white dwarf star.

    PubMed

    Nugent, Peter E; Sullivan, Mark; Cenko, S Bradley; Thomas, Rollin C; Kasen, Daniel; Howell, D Andrew; Bersier, David; Bloom, Joshua S; Kulkarni, S R; Kandrashoff, Michael T; Filippenko, Alexei V; Silverman, Jeffrey M; Marcy, Geoffrey W; Howard, Andrew W; Isaacson, Howard T; Maguire, Kate; Suzuki, Nao; Tarlton, James E; Pan, Yen-Chen; Bildsten, Lars; Fulton, Benjamin J; Parrent, Jerod T; Sand, David; Podsiadlowski, Philipp; Bianco, Federica B; Dilday, Benjamin; Graham, Melissa L; Lyman, Joe; James, Phil; Kasliwal, Mansi M; Law, Nicholas M; Quimby, Robert M; Hook, Isobel M; Walker, Emma S; Mazzali, Paolo; Pian, Elena; Ofek, Eran O; Gal-Yam, Avishay; Poznanski, Dovi

    2011-12-15

    Type Ia supernovae have been used empirically as 'standard candles' to demonstrate the acceleration of the expansion of the Universe even though fundamental details, such as the nature of their progenitor systems and how the stars explode, remain a mystery. There is consensus that a white dwarf star explodes after accreting matter in a binary system, but the secondary body could be anything from a main-sequence star to a red giant, or even another white dwarf. This uncertainty stems from the fact that no recent type Ia supernova has been discovered close enough to Earth to detect the stars before explosion. Here we report early observations of supernova SN 2011fe in the galaxy M101 at a distance from Earth of 6.4 megaparsecs. We find that the exploding star was probably a carbon-oxygen white dwarf, and from the lack of an early shock we conclude that the companion was probably a main-sequence star. Early spectroscopy shows high-velocity oxygen that slows rapidly, on a timescale of hours, and extensive mixing of newly synthesized intermediate-mass elements in the outermost layers of the supernova. A companion paper uses pre-explosion images to rule out luminous red giants and most helium stars as companions to the progenitor. PMID:22170680

  2. Supernova SN 2011fe from an exploding carbon-oxygen white dwarf star

    NASA Astrophysics Data System (ADS)

    Nugent, Peter E.; Sullivan, Mark; Cenko, S. Bradley; Thomas, Rollin C.; Kasen, Daniel; Howell, D. Andrew; Bersier, David; Bloom, Joshua S.; Kulkarni, S. R.; Kandrashoff, Michael T.; Filippenko, Alexei V.; Silverman, Jeffrey M.; Marcy, Geoffrey W.; Howard, Andrew W.; Isaacson, Howard T.; Maguire, Kate; Suzuki, Nao; Tarlton, James E.; Pan, Yen-Chen; Bildsten, Lars; Fulton, Benjamin J.; Parrent, Jerod T.; Sand, David; Podsiadlowski, Philipp; Bianco, Federica B.; Dilday, Benjamin; Graham, Melissa L.; Lyman, Joe; James, Phil; Kasliwal, Mansi M.; Law, Nicholas M.; Quimby, Robert M.; Hook, Isobel M.; Walker, Emma S.; Mazzali, Paolo; Pian, Elena; Ofek, Eran O.; Gal-Yam, Avishay; Poznanski, Dovi

    2011-12-01

    Type Ia supernovae have been used empirically as `standard candles' to demonstrate the acceleration of the expansion of the Universe even though fundamental details, such as the nature of their progenitor systems and how the stars explode, remain a mystery. There is consensus that a white dwarf star explodes after accreting matter in a binary system, but the secondary body could be anything from a main-sequence star to a red giant, or even another white dwarf. This uncertainty stems from the fact that no recent type Ia supernova has been discovered close enough to Earth to detect the stars before explosion. Here we report early observations of supernova SN 2011fe in the galaxy M101 at a distance from Earth of 6.4 megaparsecs. We find that the exploding star was probably a carbon-oxygen white dwarf, and from the lack of an early shock we conclude that the companion was probably a main-sequence star. Early spectroscopy shows high-velocity oxygen that slows rapidly, on a timescale of hours, and extensive mixing of newly synthesized intermediate-mass elements in the outermost layers of the supernova. A companion paper uses pre-explosion images to rule out luminous red giants and most helium stars as companions to the progenitor.

  3. Optical emission from a fast shock wave - The remnants of Tycho's supernova and SN 1006

    NASA Technical Reports Server (NTRS)

    Chevalier, R. A.; Raymond, J. C.

    1978-01-01

    The faint optical filaments in Tycho's supernova remnant appear to be emission from a shock front moving at 5600 km/s. The intensity of the hydrogen lines, the absence of forbidden lines of heavy elements in the spectrum, and the width of the filaments are explained by a model in which a collisionless shock wave is moving into partially neutral gas. The presence of the neutral gas can be used to set an upper limit of approximately 5 x 10 to the 47th power ergs to the energy in ionizing radiation emitted by a Type I supernova. The patchy neutral gas is probably part of the warm neutral component of the interstellar medium. The existing information on the remnant of SN 1006 indicates that its emission is similar in nature to that from Tycho's remnant.

  4. Supernova Emulators: Connecting Massively Parallel SN Ia Radiative Transfer Simulations to Data with Gaussian Processes

    NASA Astrophysics Data System (ADS)

    Goldstein, Daniel; Thomas, Rollin; Kasen, Daniel

    2015-01-01

    Collaboration between the type Ia supernova (SN Ia) modeling and observation communities hinges on our ability to directly connect simulations to data. Here we introduce supernova emulation, a method for facilitating such a connection. Emulation allows us to instantaneously predict the observables (light curves, spectra, spectral time series) generated by arbitrary SN Ia radiative transfer simulations, with estimates of prediction error. Emulators learn the mapping between physically meaningful simulation inputs and the resulting synthetic observables from a training set of simulation input-output pairs. In our emulation framework, we model PCA-decomposed representations of simulated observables as an ensemble of Gaussian Processes. As a proof of concept, we train a bolometric light curve (BLC) emulator on a grid of 400 simulation inputs and BLCs synthesized with the publicly available, gray, time-dependent Monte Carlo expanding atmospheres code, SMOKE. We emulate SMOKE simulations evaluated at a set of 100 out-of-sample input parameters, and achieve excellent agreement between the emulator predictions and the simulated BLCs. In addition to predicting simulation outputs, emulators allow us to infer the regions of simulation input parameter space that correspond to observed SN Ia light curves and spectra. We present a Bayesian framework for solving this inverse problem using Markov Chain Monte Carlo sampling. We fit published bolometric light curves with our emulator and obtain reconstructed masses (nickel mass, total ejecta mass) in agreement with reconstructions from semi-analytic models. We discuss applications of emulation to supernova cosmology and physics, including how emulators can be used to identify and quantify astrophysical sources of systematic error affecting SNe Ia as distance indicators for cosmology.

  5. SN 2009ib: a Type II-P supernova with an unusually long plateau

    NASA Astrophysics Data System (ADS)

    Takáts, K.; Pignata, G.; Pumo, M. L.; Paillas, E.; Zampieri, L.; Elias-Rosa, N.; Benetti, S.; Bufano, F.; Cappellaro, E.; Ergon, M.; Fraser, M.; Hamuy, M.; Inserra, C.; Kankare, E.; Smartt, S. J.; Stritzinger, M. D.; Van Dyk, S. D.; Haislip, J. B.; LaCluyze, A. P.; Moore, J. P.; Reichart, D.

    2015-07-01

    We present optical and near-infrared photometry and spectroscopy of SN 2009ib, a Type II-P supernova in NGC 1559. This object has moderate brightness, similar to those of the intermediate-luminosity SNe 2008in and 2009N. Its plateau phase is unusually long, lasting for about 130 d after explosion. The spectra are similar to those of the subluminous SN 2002gd, with moderate expansion velocities. We estimate the 56Ni mass produced as 0.046 ± 0.015 M⊙. We determine the distance to SN 2009ib using both the expanding photosphere method (EPM) and the standard candle method. We also apply EPM to SN 1986L, a Type II-P SN that exploded in the same galaxy. Combining the results of different methods, we conclude the distance to NGC 1559 as D = 19.8 ± 3.0 Mpc. We examine archival, pre-explosion images of the field taken with the Hubble Space Telescope, and find a faint source at the position of the SN, which has a yellow colour [(V - I)0 = 0.85 mag]. Assuming it is a single star, we estimate its initial mass as MZAMS = 20 M⊙. We also examine the possibility, that instead of the yellow source the progenitor of SN 2009ib is a red supergiant star too faint to be detected. In this case, we estimate the upper limit for the initial zero-age main sequence (ZAMS) mass of the progenitor to be ˜14-17 M⊙. In addition, we infer the physical properties of the progenitor at the explosion via hydrodynamical modelling of the observables, and estimate the total energy as ˜0.55 × 1051 erg, the pre-explosion radius as ˜400 R⊙, and the ejected envelope mass as ˜15 M⊙, which implies that the mass of the progenitor before explosion was ˜16.5-17 M⊙.

  6. UV–Optical Observation of Type Ia Supernova SN 2013dy in NGC 7250

    NASA Astrophysics Data System (ADS)

    Zhai, Qian; Zhang, Ju-Jia; Wang, Xiao-Feng; Zhang, Tian-Meng; Liu, Zheng-Wei; Brown, Peter J.; Huang, Fan; Zhao, Xu-Lin; Chang, Liang; Yi, Wei-Min; Wang, Chuan-Jun; Xin, Yu-Xin; Wang, Jian-Guo; Lun, Bao-Li; Zhang, Xi-Liang; Fan, Yu-Feng; Zheng, Xiang-Ming; Bai, Jin-Ming

    2016-05-01

    Extensive and independent observations of Type Ia supernova (SN Ia) SN 2013dy are presented, including a larger set of UBVRI photometry and optical spectra from a few days before the peak brightness to ∼ 200 days after explosion, and ultraviolet (UV) photometry spanning from t ≈ –10 days to t ≈ +15 days refers to the B band maximum. The peak brightness (i.e., MB = –19.65 ± 0.40 mag; Lmax = [1.95 ± 0.55] × 1043 erg s‑1) and the mass of synthesized 56Ni (i.e., M(56Ni) = 0.90 ± 0.26 M⊙) are calculated, and they conform to the expectation for an SN Ia with a slow decline rate (i.e., Δm15(B) = 0.90 ± 0.03 mag). However, the near infrared (NIR) brightness of this SN (i.e., MH = –17.33 ± 0.30 mag) is at least 1.0 mag fainter than usual. Besides, spectroscopy classification reveals that SN 2013dy resides on the border of “core normal” and “shallow silicon” subclasses in the Branch et al. classification scheme, or on the border of the “normal velocity” SNe Ia and 91T/99aa-like events in the Wang et al. system. These suggest that SN 2013dy is a slow-declining SN Ia located on the transitional region of nominal spectroscopic subclasses and might not be a typical normal sample of SNe Ia.

  7. Soft X-ray emission from the Lupus Loop and Sn 1006 supernova remnants

    NASA Technical Reports Server (NTRS)

    Winkler, P. F., Jr.; Hearn, D. R.; Richardson, J. A.; Behnken, J. M.

    1979-01-01

    X-ray maps of the Lupus region have been obtained in a raster scan observation from SAS 3. These show the Lupus Loop to be a faint extended source of soft X-rays with a temperature about 2.5 million K. The most prominent feature of the region is the A.D. 1006 supernova remnant, which is unexpectedly bright at 0.2-1.0 keV. One speculative interpretation of the low-energy flux from SN 1006 is as blackbody radiation from a hot neutron star.

  8. PTF Discovery of PTF10yow (SN2010iq), a Type Ic Supernova

    NASA Astrophysics Data System (ADS)

    Arcavi, I.; Maguire, K.; Kasliwal, M. M.; Ben-Ami, S.; Sternberg, A.; Horesh, A.; Sesar, B.; Yaron, O.; Gal-Yam, A.; Sullivan, M.; Quimby, R. M.; Ofek, E. O.; Kulkarni, S. R.; Nugent, P.; Bloom, J. S.; Silverman, J. M.; Law, N. M.

    2010-11-01

    The PTF (ATEL #1964; http://www.astro.caltech.edu/ptf/) reports the discovery of PTF10yow (also discovered independently by LOSS as SN2010iq; IAUC 2493). The supernova was discovered by Oarical, an autonomous software framework of the PTF collaboration, on October 2 UT at RA(J2000) = 21:54:23.30 and DEC(J2000) = +15:09:20.7 at a magnitude of 18.5 in R-band (calibrated with respect to the USNO catalog) in the galaxy IC 5145 (z=0.0245).

  9. Five Years in the Mid-Infrared Development of the SN 1987A Supernova Remnant

    NASA Technical Reports Server (NTRS)

    Dwek, Eliahu

    2009-01-01

    Spitzer has been used to monitor the mid-IR evolution of SN 1987A over a 5 year period as it develops into a supernova remnant through interaction with its surrounding environment. This interaction is dominated by the collision of the ejecta with the pre-existing equatorial ring. The mid-IR continuum indicates an increasing mass of shock-heated silicate dust, but without any significant change in temperature of the dust grains. Comparison of the IR and X-ray evolution of the remnant can be used to infer plasma conditions and the processing of the dust in the shock-heated X-ray emitting gas.

  10. The End of Amnesia: Measuring the Metallicities of Type Ia SN Progenitors with Manganese Lines in Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Badenes, Carles; Bravo, Eduardo; Hughes, John P.

    2009-05-01

    The Mn to Cr mass ratio in supernova ejecta has recently been proposed as a tracer of Type Ia SN progenitor metallicity. We review the advantages and problems of this observable quantity, and discuss them in the framework of the Tycho Supernova Remnant. The fluxes of the Mn and Cr Kα lines in the X-ray spectra of Tycho observed by the Suzaku satellite suggests a progenitors of supersolar metallicity.

  11. X-ray characteristics of the Lupus Loop and SN 1006 supernova remnants

    SciTech Connect

    Toor, A.

    1980-01-01

    The spatial extent of the Lupus Loop and spectra for the Lupus Loop and SN1006 supernova remnants have been determined with a rocket-borne payload. The Lupus Loop is an extended source of soft X-rays (approx. 300' diam) that shows a correlation between its brightest x-ray and radio-emission regions. Its spectrum is characterized by a temperature of 350 eV. Thus, the Lupus Loop appears similar to Vela X and Cygnus Loop, although much weaker. Emission from SN1006 is spatially unresolved and exhibits a harder spectrum than that of the Lupus Loop. All spectral data (0.2 to 10 keV) from our observation and previous observations are satisfactorily fit with a power law (index = 2.15). This spectral dependence suggests the possibility that a rotating neutron star is the underlying source of the radiated energy although such an interpretation appears inconsistent with the remnant's morphology.

  12. SN~2012cg: Evidence for Interaction Between a Normal Type Ia Supernova and a Non-degenerate Binary Companion

    NASA Astrophysics Data System (ADS)

    Marion, G. H.; Brown, Peter J.; Vinkó, Jozsef; Silverman, Jeffrey M.; Sand, David J.; Challis, Peter; Kirshner, Robert P.; Wheeler, J. Craig; Berlind, Perry; Brown, Warren R.; Calkins, Michael L.; Camacho, Yssavo; Dhungana, Govinda; Foley, Ryan J.; Friedman, Andrew S.; Graham, Melissa L.; Howell, D. Andrew; Hsiao, Eric Y.; Irwin, Jonathan M.; Jha, Saurabh W.; Kehoe, Robert; Macri, Lucas M.; Maeda, Keiichi; Mandel, Kaisey; McCully, Curtis; Pandya, Viraj; Rines, Kenneth J.; Wilhelmy, Steven; Zheng, Weikang

    2016-04-01

    We report evidence for excess blue light from the Type Ia supernova (Sn Ia) SN 2012cg at 15 and 16 days before maximum B-band brightness. The emission is consistent with predictions for the impact of the supernova on a non-degenerate binary companion. This is the first evidence for emission from a companion to a normal SN Ia. Sixteen days before maximum light, the B-V color of SN 2012cg is 0.2 mag bluer than for other normal SN Ia. At later times, this supernova has a typical SN Ia light curve, with extinction-corrected {M}B=-19.62+/- 0.02 mag and {{Δ }}{m}15(B)=0.86+/- 0.02. Our data set is extensive, with photometry in seven filters from five independent sources. Early spectra also show the effects of blue light, and high-velocity features are observed at early times. Near maximum, the spectra are normal with a silicon velocity vSi = -10,500 km s-1. Comparing the early data with models by Kasen favors a main-sequence companion of about six solar masses. It is possible that many other SN Ia have main-sequence companions that have eluded detection because the emission from the impact is fleeting and faint.

  13. Hubble Space Telescope And Ground-based Observations Of SN 2005hk And SN 2008a: SN 2002cx-like Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    McCully, Curtis; Jha, S. W.; Foley, R. J.; Garnavich, P. M.

    2011-01-01

    Type Ia supernovae (SNe Ia) have been very successful tools for studying the history of cosmic expansion and led to the discovery of the accelerating universe and dark energy. However, the explosion mechanism and progenitors for SNe Ia are still not fundamentally well understood. We present results from late time (up to 600 days past maximum brightness) HST and ground based observations of two typical members of the SN 2002cx-like subclass of peculiar SNe Ia: SN 2005hk and SN 2008A. At late times, these objects are characterized by significant amounts of high density, low velocity material giving a unique opportunity to resolve spectral features that are blended in normal SNe Ia. We identify permitted Fe I and Fe II lines, allowing us to calculate a characteristic temperature, and use the ratio between permitted and forbidden Ca II lines to constrain the density. We find that the density stays extraordinarily high out to late phases, implying enhanced cooling. However, we do not confirm the presence of the "infrared catastrophe” that is generically predicted by SN models as the ejecta cools. We also constrain explosion models for these objects: the lack of [0 I] 6300 A emission allows us to rule out the possibility that these peculiar objects are pure deflagration explosions that leave large amounts of unburned material in the innermost layers of the ejecta. Understanding what makes these SNe so different from their normal cousins has the promise to clarify these key systematic uncertainties in their use for cosmology.

  14. Type II Supernova Energetics and Comparison of Light Curves to Shock-cooling Models

    NASA Astrophysics Data System (ADS)

    Rubin, Adam; Gal-Yam, Avishay; De Cia, Annalisa; Horesh, Assaf; Khazov, Danny; Ofek, Eran O.; Kulkarni, S. R.; Arcavi, Iair; Manulis, Ilan; Yaron, Ofer; Vreeswijk, Paul; Kasliwal, Mansi M.; Ben-Ami, Sagi; Perley, Daniel A.; Cao, Yi; Cenko, S. Bradley; Rebbapragada, Umaa D.; Woźniak, P. R.; Filippenko, Alexei V.; Clubb, K. I.; Nugent, Peter E.; Pan, Y.-C.; Badenes, C.; Howell, D. Andrew; Valenti, Stefano; Sand, David; Sollerman, J.; Johansson, Joel; Leonard, Douglas C.; Horst, J. Chuck; Armen, Stephen F.; Fedrow, Joseph M.; Quimby, Robert M.; Mazzali, Paulo; Pian, Elena; Sternberg, Assaf; Matheson, Thomas; Sullivan, M.; Maguire, K.; Lazarevic, Sanja

    2016-03-01

    During the first few days after explosion, Type II supernovae (SNe) are dominated by relatively simple physics. Theoretical predictions regarding early-time SN light curves in the ultraviolet (UV) and optical bands are thus quite robust. We present, for the first time, a sample of 57 R-band SN II light curves that are well-monitored during their rise, with \\gt 5 detections during the first 10 days after discovery, and a well-constrained time of explosion to within 1-3 days. We show that the energy per unit mass (E/M) can be deduced to roughly a factor of five by comparing early-time optical data to the 2011 model of Rabinak & Waxman, while the progenitor radius cannot be determined based on R-band data alone. We find that SN II explosion energies span a range of E/M = (0.2-20) × 1051 erg/(10 {M}⊙ ), and have a mean energy per unit mass of < E/M> =0.85× {10}51 erg/(10 {M}⊙ ), corrected for Malmquist bias. Assuming a small spread in progenitor masses, this indicates a large intrinsic diversity in explosion energy. Moreover, E/M is positively correlated with the amount of 56Ni produced in the explosion, as predicted by some recent models of core-collapse SNe. We further present several empirical correlations. The peak magnitude is correlated with the decline rate ({{Δ }}{m}15), the decline rate is weakly correlated with the rise time, and the rise time is not significantly correlated with the peak magnitude. Faster declining SNe are more luminous and have longer rise times. This limits the possible power sources for such events.

  15. Type Ib SN 1999dn as an example of the thoroughly mixed ejecta of Ib supernovae

    NASA Astrophysics Data System (ADS)

    Cano, Zach; Maeda, Keiichi; Schulze, Steve

    2014-03-01

    We present the results of modelling archival observations of Type Ib SN 1999dn. In the spectra, two He I absorption features are seen: a slower component with larger opacity, and a more rapid He I component with smaller opacity. Complementary results are obtained from modelling the bolometric light curve of SN 1999dn, where a two-zone model (dense inner region, and less dense outer region) provides a much better fit than a one-zone model. A key result we find is that roughly equal amounts of radioactive material are found in both regions. The two-zone analytical model provides a more realistic representation of the structure of the ejecta, including mixing and asymmetries, which offers a physical explanation for how the radioactive material is propelled to, and mixed within, the outer regions. Our result supports the theoretical expectation that the radioactive content in the outflow of a Type Ib supernova (SN) is thoroughly mixed. We fit our model to six additional SNe Ibc, of which the majority of the SNe Ib are best described by the two-zone model, and the majority of the SNe Ic by the one-zone model. Of the SNe Ic, only SN 2007gr was best fitted by the two-zone model, indicating that the lack of helium spectral features for this event cannot be attributed to poor mixing.

  16. SN 1994I in M51 and the nature of type Ibc supernovae

    NASA Technical Reports Server (NTRS)

    Wheeler, J. C.; Harkness, R. P.; Clocchiatti, A.; Benetti, S.; Brotherton, M. S.; Depoy, D. L.; Elias, J.

    1994-01-01

    Early spectra of SN 1994I in M51 (NGC 5194) are presented along with arguments that is a member of the class of helium-poor Type Ic supernovae. The issue of H and He in the spectra of Type Ib and Ic events is reexamined with the conclusion that Type Ib eject substantially less H than even transition events like SN 1993J and that Type Ic eject substantially less He than Type Ib and their optical spectra are consistent with no H or He. Type Ic show and absorption of the Si II lambda 6355 blend that characterizes Type Ia. This feature requires only a solar abundance of Si. Some Type Ic show an absorption that is probably C II lambda 6580. IR spectra are presented of SN 1990W which show the line of He I lambda 10830. The strength of this feature and the rather slow decay of the late time light curve suggest that this event could be better classified as a Type Ib. Even if trace abundances of H are present in Type Ib and of He in Type Ic the spectral differences still imply a distinctly different evolution for the progenitors of Type Ib from Type Ic and events like SN 1993J.

  17. Optical observations of the broad-lined type Ic supernova SN 2012ap

    NASA Astrophysics Data System (ADS)

    Liu, Zheng; Zhao, Xu-Lin; Huang, Fang; Wang, Xiao-Feng; Zhang, Tian-Meng; Chen, Jun-Cheng; Zhang, Tong-Jie

    2015-02-01

    The optical observations of the type Ic supernova (SN Ic) SN 2012ap in NGC 1729 are presented. A comparison with other SNe Ic indicates that SN 2012ap is highly reddened (with E(B — V)host~0.8 mag) and may represent one of the most luminous SNe Ic ever observed, with an absolute V-band peak magnitude of ~ -19.3±0.5 mag after extinction correction. The near-maximum-light spectrum shows wide spectral features that are typical of broad-lined SNe Ic. One interesting feature in the spectrum is the appearance of some narrow absorption features that can be attributed to the diffuse interstellar bands, consistent with the large reddening inferred from the photometric method. Based on the light curves and the spectral data, we estimate that SN 2012ap produced a 56Ni mass of ~ 0.3 ± 0.1Msolar 1 in the explosion, with an ejecta mass of 2.4-0.7+0.7Msolar and a kinetic energy of EK = 1.1-0.4+0.4 × 1052 erg. The properties of its progenitor are also briefly discussed.

  18. SN Refsdal: Photometry and Time Delay Measurements of the First Einstein Cross Supernova

    NASA Astrophysics Data System (ADS)

    Rodney, S. A.; Strolger, L.-G.; Kelly, P. L.; Bradač, M.; Brammer, G.; Filippenko, A. V.; Foley, R. J.; Graur, O.; Hjorth, J.; Jha, S. W.; McCully, C.; Molino, A.; Riess, A. G.; Schmidt, K. B.; Selsing, J.; Sharon, K.; Treu, T.; Weiner, B. J.; Zitrin, A.

    2016-03-01

    We present the first year of Hubble Space Telescope imaging of the unique supernova (SN) “Refsdal,” a gravitationally lensed SN at z = 1.488 ± 0.001 with multiple images behind the galaxy cluster MACS J1149.6+2223. The first four observed images of SN Refsdal (images S1-S4) exhibited a slow rise (over ˜150 days) to reach a broad peak brightness around 2015 April 20. Using a set of light curve templates constructed from SN 1987A-like peculiar Type II SNe, we measure time delays for the four images relative to S1 of 4 ± 4 (for S2), 2 ± 5 (S3), and 24 ± 7 days (S4). The measured magnification ratios relative to S1 are 1.15 ± 0.05 (S2), 1.01 ± 0.04 (S3), and 0.34 ± 0.02 (S4). None of the template light curves fully captures the photometric behavior of SN Refsdal, so we also derive complementary measurements for these parameters using polynomials to represent the intrinsic light curve shape. These more flexible fits deliver fully consistent time delays of 7 ± 2 (S2), 0.6 ± 3 (S3), and 27 ± 8 days (S4). The lensing magnification ratios are similarly consistent, measured as 1.17 ± 0.02 (S2), 1.00 ± 0.01 (S3), and 0.38 ± 0.02 (S4). We compare these measurements against published predictions from lens models, and find that the majority of model predictions are in very good agreement with our measurements. Finally, we discuss avenues for future improvement of time delay measurements—both for SN Refsdal and for other strongly lensed SNe yet to come.

  19. Recurring X-ray outbursts in the supernova impostor SN 2010da in NGC 300

    NASA Astrophysics Data System (ADS)

    Binder, B.; Williams, B. F.; Kong, A. K. H.; Gaetz, T. J.; Plucinsky, P. P.; Skillman, E. D.; Dolphin, A.

    2016-04-01

    We present new observations of the `supernova impostor' SN 2010da using the Chandra X-ray Observatory and the Hubble Space Telescope. During the initial 2010 outburst, the 0.3-10 keV luminosity was observed by Swift to be ˜5 × 1038 erg s-1 and faded by a factor of ˜25 in a four month period. Our two new Chandra observations show a factor of ˜10 increase in the 0.35-8 keV X-ray luminosity, from ˜4 × 1036 to 4 × 1037 erg s-1 in ˜6 months, and the X-ray spectrum is consistent in both observations with a power-law with a photon index of Γ ˜ 0. We find evidence of X-ray spectral state changes: when SN 2010da is in a high-luminosity state, the X-ray spectrum is harder (Γ ˜0) compared to the low-luminosity state (Γ ˜ 1.2 ± 0.8). Using our Hubble observations, we fit the colour-magnitude diagram of the coeval stellar population to estimate a time since formation of the SN 2010da progenitor system of ≲5 Myr. Our observations are consistent with SN 2010da being a high-mass X-ray binary (HMXB) composed of a neutron star and a luminous blue variable-like companion, although we cannot rule out the possibility that SN 2010da is an unusually X-ray bright massive star. The ≲5 Myr age is consistent with the theoretically predicted delay time between the formation of a massive binary and the onset of the HMXB phase. It is possible that the initial 2010 outburst marked the beginning of X-ray production in the system, making SN 2010da possibly the first massive progenitor binary ever observed to evolve into an HMXB.

  20. Comprehensive observations of the bright and energetic Type Iax SN 2012Z: Interpretation as a Chandrasekhar mass white dwarf explosion

    NASA Astrophysics Data System (ADS)

    Stritzinger, M. D.; Valenti, S.; Hoeflich, P.; Baron, E.; Phillips, M. M.; Taddia, F.; Foley, R. J.; Hsiao, E. Y.; Jha, S. W.; McCully, C.; Pandya, V.; Simon, J. D.; Benetti, S.; Brown, P. J.; Burns, C. R.; Campillay, A.; Contreras, C.; Förster, F.; Holmbo, S.; Marion, G. H.; Morrell, N.; Pignata, G.

    2015-01-01

    We present ultraviolet through near-infrared (NIR) broadband photometry, and visual-wavelength and NIR spectroscopy of the Type Iax supernova (SN) 2012Z. The data set consists of both early- and late-time observations, including the first late phase NIR spectrum obtained for a spectroscopically classified SN Iax. Simple model calculations of its bolometric light curve suggest SN 2012Z produced ~0.3 M⊙ of 56Ni, ejected about a Chandrasekhar mass of material, and had an explosion energy of ~1051 erg, making it one of the brightest (MB = -18.3 mag) and most energetic SN Iax yet observed. The late phase (+269d) NIRspectrum of SN 2012Z is found to broadly resemble similar epoch spectra of normal SNe Ia; however, like other SNe Iax, corresponding visual-wavelength spectra differ substantially from all supernova types. Constraints from the distribution of intermediate mass elements, e.g., silicon and magnesium, indicate that the outer ejecta did not experience significant mixing during or after burning, and the late phase NIR line profiles suggests most of the 56Ni is produced during high density burning. The various observational properties of SN 2012Z are found to be consistent with the theoretical expectations of a Chandrasekhar mass white dwarf progenitor that experiences a pulsational delayed detonation, which produced several tenths of a solar mass of 56Ni during the deflagration burning phase and little (or no) 56Ni during the detonation phase. Within this scenario only a moderate amount of Rayleigh-Taylor mixing occurs both during the deflagration and fallback phase of the pulsation, and the layered structure of the intermediate mass elements is a product of the subsequent denotation phase. The fact that the SNe Iax population does not follow a tight brightness-decline relation similar to SNe Ia can then be understood in the framework of variable amounts of mixing during pulsational rebound and variable amounts of 56Ni production during the early subsonic phase

  1. Type IIP supernovae as cosmological probes: A SEAM distance to SN1999em

    SciTech Connect

    Baron, E.; Nugent, Peter E.; Branch, David; Hauschildt, Peter H.

    2004-06-01

    Because of their intrinsic brightness, supernovae make excellent cosmological probes. We describe the spectral-fitting expanding atmosphere method (SEAM) for obtaining distances to Type IIP supernovae (SNe IIP) and present a distance to SN 1999em for which a Cepheid distance exists. Our models give results consistent with the Cepheid distance, even though we have not attempted to tune the underlying hydrodynamical model but have simply chosen the best fits. This is in contradistinction to the expanding photosphere method (EPM), which yields a distance to SN 1999em that is 50 percent smaller than the Cepheid distance. We emphasize the differences between the SEAM and the EPM. We show that the dilution factors used in the EPM analysis were systematically too small at later epochs. We also show that the EPM blackbody assumption is suspect. Since SNe IIP are visible to redshifts as high as z {approx}< 6, with the James Webb Space Telescope, the SEAM may be a valuable probe of the early universe.

  2. Radio emission and nonlinear diffusive shock acceleration of cosmic rays in the supernova SN 1993J

    NASA Astrophysics Data System (ADS)

    Tatischeff, V.

    2009-05-01

    Aims: The extensive observations of the supernova SN 1993J at radio wavelengths make this object a unique target for the study of particle acceleration in a supernova shock. Methods: To describe the radio synchrotron emission we use a model that couples a semianalytic description of nonlinear diffusive shock acceleration with self-similar solutions for the hydrodynamics of the supernova expansion. The synchrotron emission, which is assumed to be produced by relativistic electrons propagating in the postshock plasma, is worked out from radiative transfer calculations that include the process of synchrotron self-absorption. The model is applied to explain the morphology of the radio emission deduced from high-resolution VLBI imaging observations and the measured time evolution of the total flux density at six frequencies. Results: Both the light curves and the morphology of the radio emission indicate that the magnetic field was strongly amplified in the blast wave region shortly after the explosion, possibly via the nonresonant regime of the cosmic-ray streaming instability operating in the shock precursor. The amplified magnetic field immediately upstream from the subshock is determined to be Bu ≈ 50 (t/1 { day})-1 G. The turbulent magnetic field was not damped behind the shock but carried along by the plasma flow in the downstream region. Cosmic-ray protons were efficiently produced by diffusive shock acceleration at the blast wave. We find that during the first 8.5 years after the explosion, about 19% of the total energy processed by the forward shock was converted to cosmic-ray energy. However, the shock remained weakly modified by the cosmic-ray pressure. The high magnetic field amplification implies that protons were rapidly accelerated to energies well above 1015 eV. The results obtained for this supernova support the scenario that massive stars exploding into their former stellar wind are a major source of Galactic cosmic-rays of energies above 1015 eV. We

  3. Photometric and spectroscopic observations, and abundance tomography modelling of the Type Ia supernova SN 2014J located in M82

    NASA Astrophysics Data System (ADS)

    Ashall, C.; Mazzali, P.; Bersier, D.; Hachinger, S.; Phillips, M.; Percival, S.; James, P.; Maguire, K.

    2014-12-01

    Spectroscopic and photometric observations of the nearby Type Ia Supernova (SN Ia) SN 2014J are presented. Spectroscopic observations were taken -8 to +10 d relative to B-band maximum, using FRODOSpec, a multipurpose integral-field unit spectrograph. The observations range from 3900 to 9000 Å. SN 2014J is located in M82 which makes it the closest SN Ia studied in at least the last 28 yr. It is a spectroscopically normal SN Ia with high-velocity features. We model the spectra of SN 2014J with a Monte Carlo radiative transfer code, using the abundance tomography technique. SN 2014J is highly reddened, with a host galaxy extinction of E(B - V) = 1.2 (RV = 1.38). It has a Δm15(B) of 1.08 ± 0.03 when corrected for extinction. As SN 2014J is a normal SN Ia, the density structure of the classical W7 model was selected. The model and photometric luminosities are both consistent with B-band maximum occurring on JD 245 6690.4 ± 0.12. The abundance of the SN 2014J behaves like other normal SN Ia, with significant amounts of silicon (12 per cent by mass) and sulphur (9 per cent by mass) at high velocities (12 300 km s-1) and the low-velocity ejecta (v < 6500 km s-1) consists almost entirely of 56Ni.

  4. Multi-dimensional simulations of the expanding supernova remnant of SN 1987A

    SciTech Connect

    Potter, T. M.; Staveley-Smith, L.; Reville, B.; Ng, C.-Y.; Bicknell, G. V.; Sutherland, R. S.; Wagner, A. Y.

    2014-10-20

    The expanding remnant from SN 1987A is an excellent laboratory for investigating the physics of supernovae explosions. There is still a large number of outstanding questions, such as the reason for the asymmetric radio morphology, the structure of the pre-supernova environment, and the efficiency of particle acceleration at the supernova shock. We explore these questions using three-dimensional simulations of the expanding remnant between days 820 and 10,000 after the supernova. We combine a hydrodynamical simulation with semi-analytic treatments of diffusive shock acceleration and magnetic field amplification to derive radio emission as part of an inverse problem. Simulations show that an asymmetric explosion, combined with magnetic field amplification at the expanding shock, is able to replicate the persistent one-sided radio morphology of the remnant. We use an asymmetric Truelove and McKee progenitor with an envelope mass of 10 M {sub ☉} and an energy of 1.5 × 10{sup 44} J. A termination shock in the progenitor's stellar wind at a distance of 0.''43-0.''51 provides a good fit to the turn on of radio emission around day 1200. For the H II region, a minimum distance of 0.''63 ± 0.''01 and maximum particle number density of (7.11 ± 1.78) × 10{sup 7} m{sup –3} produces a good fit to the evolving average radius and velocity of the expanding shocks from day 2000 to day 7000 after explosion. The model predicts a noticeable reduction, and possibly a temporary reversal, in the asymmetric radio morphology of the remnant after day 7000, when the forward shock left the eastern lobe of the equatorial ring.

  5. Multi-dimensional Simulations of the Expanding Supernova Remnant of SN 1987A

    NASA Astrophysics Data System (ADS)

    Potter, T. M.; Staveley-Smith, L.; Reville, B.; Ng, C.-Y.; Bicknell, G. V.; Sutherland, R. S.; Wagner, A. Y.

    2014-10-01

    The expanding remnant from SN 1987A is an excellent laboratory for investigating the physics of supernovae explosions. There is still a large number of outstanding questions, such as the reason for the asymmetric radio morphology, the structure of the pre-supernova environment, and the efficiency of particle acceleration at the supernova shock. We explore these questions using three-dimensional simulations of the expanding remnant between days 820 and 10,000 after the supernova. We combine a hydrodynamical simulation with semi-analytic treatments of diffusive shock acceleration and magnetic field amplification to derive radio emission as part of an inverse problem. Simulations show that an asymmetric explosion, combined with magnetic field amplification at the expanding shock, is able to replicate the persistent one-sided radio morphology of the remnant. We use an asymmetric Truelove & McKee progenitor with an envelope mass of 10 M ⊙ and an energy of 1.5 × 1044 J. A termination shock in the progenitor's stellar wind at a distance of 0.''43-0.''51 provides a good fit to the turn on of radio emission around day 1200. For the H II region, a minimum distance of 0.''63 ± 0.''01 and maximum particle number density of (7.11 ± 1.78) × 107 m-3 produces a good fit to the evolving average radius and velocity of the expanding shocks from day 2000 to day 7000 after explosion. The model predicts a noticeable reduction, and possibly a temporary reversal, in the asymmetric radio morphology of the remnant after day 7000, when the forward shock left the eastern lobe of the equatorial ring.

  6. TYPE IIn SUPERNOVA SN 2010jl: OPTICAL OBSERVATIONS FOR OVER 500 DAYS AFTER EXPLOSION

    SciTech Connect

    Zhang Tianmeng; Wu Chao; Zhai Meng; Wu Hong; Fan Zhou; Zou Hu; Zhou Xu; Ma Jun; Wang Xiaofeng; Chen Juncheng; Chen Jia; Liu Qin; Huang Fang; Liang Jide; Zhao Xulin; Lin Lin; Wang Min; Dennefeld, Michel; Zhang Jujia E-mail: wang_xf@mail.tsinghua.edu.cn

    2012-11-01

    We present extensive optical observations of a Type IIn supernova (SN IIn) 2010jl for the first 1.5 years after its discovery. The UBVRI light curves demonstrated an interesting two-stage evolution during the nebular phase, which almost flatten out after about 90 days from the optical maximum. SN 2010jl has one of the highest intrinsic H{alpha} luminosities ever recorded for an SN IIn, especially at late phase, suggesting a strong interaction of SN ejecta with the dense circumstellar material (CSM) ejected by the progenitor. This is also indicated by the remarkably strong Balmer lines persisting in the optical spectra. One interesting spectral evolution about SN 2010jl is the appearance of asymmetry of the Balmer lines. These lines can be well decomposed into a narrow component and an intermediate-width component. The intermediate-width component showed a steady increase in both strength and blueshift with time until t {approx} 400 days after maximum, but it became less blueshifted at t {approx} 500 days, when the line profile appeared relatively symmetric again. Owing to the fact that a pure reddening effect will lead to a sudden decline of the light curves and a progressive blueshift of the spectral lines, we therefore propose that the asymmetric profiles of H lines seen in SN 2010jl are unlikely due to the extinction by newly formed dust inside the ejecta, contrary to the explanation by some early studies. Based on a simple CSM-interaction model, we speculate that the progenitor of SN 2010jl may suffer a gigantic mass loss ({approx}30-50 M{sub Sun }) a few decades before explosion. Considering a slow-moving stellar wind (e.g., {approx}28 km s{sup -1}) inferred for the preexisting, dense CSM shell and the extremely high mass-loss rate (1-2 M{sub Sun} yr{sup -1}), we suggest that the progenitor of SN 2010jl might have experienced a red supergiant stage and may explode finally as a post-red supergiant star with an initial mass above 30-40 M{sub Sun }.

  7. Spectroscopic Classification of SN 2016cnv (=PTSS-16gyb) as a Type Ia Supernova (corrections for ATel#9083)

    NASA Astrophysics Data System (ADS)

    Zhang, Jujia; Zheng, Xiangming; Wang, Xiaofeng; Li, Wenxiong; Yang, Zesheng; Li, Bin; Xu, Zhijian; Zhao, Haibin; Wang, Lifan

    2016-05-01

    We obtained an optical spectrum (range 340-900 nm) of SN 2016cnv (=PTSS-16gyb), discovered by the PMO-Tsinghua Supernova Survey (PTSS: http://119.78.210.3/ptss2/), on UT May 26.71 2016 with the 2.4 m telescope (LJT + YFOSC) at LiJiang Observatory of Yunnan Observatories (YNAO).

  8. SALT spectroscopic classification of PS16atu (SN 2016atv) as a type-Ia supernova after maximum light

    NASA Astrophysics Data System (ADS)

    Jha, S. W.; Pan, Y.-C.; Foley, R. J.; Rest, A.; Scolnic, D.; Kotze, M.

    2016-03-01

    We obtained SALT (+RSS) spectroscopy of PS16atu (SN 2016atv) on 2016 Mar 10.1 UT, covering the wavelength range 350-920 nm. Cross-correlation of the spectrum with a template library using SNID (Blondin & Tonry 2007, ApJ, 666, 1024) shows PS16atu is a type-Ia supernova approximately a week past maximum light.

  9. HIGH RESOLUTION 36 GHz IMAGING OF THE SUPERNOVA REMNANT OF SN 1987A

    SciTech Connect

    Potter, T. M.; Staveley-Smith, L.; Zanardo, G.; Ng, C.-Y.; Gaensler, B. M.; Ball, Lewis; Kesteven, M. J.; Manchester, R. N.; Tzioumis, A. K.

    2009-11-01

    The aftermath of supernova (SN) 1987A continues to provide spectacular insights into the interaction between an SN blastwave and its circumstellar environment. We here present 36 GHz observations from the Australia Telescope Compact Array of the radio remnant of SN 1987A. These new images, taken in 2008 April and 2008 October, substantially extend the frequency range of an ongoing monitoring and imaging program conducted between 1.4 and 20 GHz. Our 36.2 GHz images have a diffraction-limited angular resolution of 0.''3-0.''4, which covers the gap between high resolution, low dynamic range VLBI images of the remnant and low resolution, high dynamic range images at frequencies between 1 and 20 GHz. The radio morphology of the remnant at 36 GHz is an elliptical ring with enhanced emission on the eastern and western sides, similar to that seen previously at lower frequencies. Model fits to the data in the Fourier domain show that the emitting region is consistent with a thick inclined torus of mean radius 0.''85, and a 2008 October flux density of 27 +- 6 mJy at 36.2 GHz. The spectral index for the remnant at this epoch, determined between 1.4 GHz and 36.2 GHz, is alpha = -0.83. There is tentative evidence for an unresolved central source with flatter spectral index.

  10. SN 2014J at M82 - I. A middle-class Type Ia supernova by all spectroscopic metrics

    NASA Astrophysics Data System (ADS)

    Galbany, L.; Moreno-Raya, M. E.; Ruiz-Lapuente, P.; González Hernández, J. I.; Méndez, J.; Vallely, P.; Baron, E.; Domínguez, I.; Hamuy, M.; López-Sánchez, A. R.; Mollá, M.; Catalán, S.; Cooke, E. A.; Fariña, C.; Génova-Santos, R.; Karjalainen, R.; Lietzen, H.; McCormac, J.; Riddick, F. C.; Rubiño-Martín, J. A.; Skillen, I.; Tudor, V.; Vaduvescu, O.

    2016-03-01

    We present the intensive spectroscopic follow up of the Type Ia supernova (SN Ia) 2014J in the starburst galaxy M82. Twenty-seven optical spectra have been acquired from 2014 January 22 to September 1 with the Isaac Newton and William Herschel Telescopes. After correcting the observations for the recession velocity of M82 and for Milky Way and host galaxy extinction, we measured expansion velocities from spectral line blueshifts and pseudo-equivalent width of the strongest features in the spectra, which gives an idea on how elements are distributed within the ejecta. We position SN 2014J in the Benetti, Branch et al. and Wang et al. diagrams. These diagrams are based on properties of the Si II features and provide dynamical and chemical information about the SN ejecta. The nearby SN 2011fe, which showed little evidence for reddening in its host galaxy, is shown as a reference for comparisons. SN 2014J is a border-line object between the Core-normal and Broad-line groups, which corresponds to an intermediate position between low-velocity gradient and high-velocity gradient objects. SN 2014J follows the R(Si II)-Δm15 correlation, which confirms its classification as a relatively normal SN Ia. Our description of the SN Ia in terms of the evolution of the pseudo-equivalent width of various ions as well as the position in the various diagrams put this specific SN Ia into the overall sample of SN Ia.

  11. Unveiling Type IIb Supernova Progenitors: SN 2011hs from a Supergiant Star

    NASA Astrophysics Data System (ADS)

    Bufano, F.

    2014-10-01

    Type IIb Supernovae are the final evolutionary stage of massive stars that were able to retain only a thin (lesssim 1 M_{odot}) H/He external envelope at the time of the explosion. The mechanism of mass-loss that made such final structure possible and the nature of such progenitor stars are still open issues. We present the results obtained from the study of a sample of Type IIb SNe, in particular, of SN 2011hs (Bufano et al., 2013, MNRAS submitted). SN 2011hs was a relatively faint (M_{B} = -15.6 mag) and red Type IIb SN, characterized by a narrow light curve shape. Its spectral evolution showed the metamorphosis typical of this class of SN, from spectra dominated by H I lines to spectra where He I features dominate, but with broad absorption line profiles indicating high expansion velocities. Modeling the light curve of SN 2011hs and its velocity evolution with hydrodynamical calculations, we estimated that the SN is consistent with the explosion of a 3-4 M_{odot} He-core star, from a main sequence mass of 12-15 M_{odot}, ejecting a ^{56}Ni mass equal to 0.04 M_{odot} and characterized by an explosion energy of E≍ 8.5× 10^{50} erg s^{-1}. Based on the light curve evolution, we assumed that the explosion occurred 6 days before the discovery (2,455,872 ± 4 JD), resulting in an adiabatic cooling phase lasting 8 days, similarly to SN 1993J. Since the duration and the decreasing rate of the cooling branch depends mainly on the progenitor size, we could infer from it a progenitor radius of ≍ 500-600 R_{odot}, like a supergiant star. Our modeling rules out models with He core mass >5 M_{odot}, i.e. main sequence masses above 20 M_{odot}. Such a lower limit for the progenitor mass could indicate the possibility of a binary origin, although the radio light curve does not show strong deviations, typically signature of the presence of a companion star.

  12. SN 2010LP—A TYPE IA SUPERNOVA FROM A VIOLENT MERGER OF TWO CARBON-OXYGEN WHITE DWARFS

    SciTech Connect

    Kromer, M.; Taubenberger, S.; Seitenzahl, I. R.; Hillebrandt, W.; Pakmor, R.; Pignata, G.; Fink, M.; Röpke, F. K.; Sim, S. A.

    2013-11-20

    SN 2010lp is a subluminous Type Ia supernova (SN Ia) with slowly evolving lightcurves. Moreover, it is the only subluminous SN Ia observed so far that shows narrow emission lines of [O I] in late-time spectra, indicating unburned oxygen close to the center of the ejecta. Most explosion models for SNe Ia cannot explain the narrow [O I] emission. Here, we present hydrodynamic explosion and radiative transfer calculations showing that the violent merger of two carbon-oxygen white dwarfs of 0.9 and 0.76 M {sub ☉} adequately reproduces the early-time observables of SN 2010lp. Moreover, our model predicts oxygen close to the center of the explosion ejecta, a pre-requisite for narrow [O I] emission in nebular spectra as observed in SN 2010lp.

  13. Host galaxy spectra and consequences for supernova typing from the SDSS SN survey

    SciTech Connect

    Olmstead, Matthew D.; Brown, Peter J.; Brownstein, Joel R.; Dawson, Kyle S.; Sako, Masao; Gupta, Ravi R.; Bassett, Bruce; Kunz, Martin; Bizyaev, Dmitry; Brinkmann, J.; Brewington, Howard; Ebelke, Garrett L.; Campbell, Heather; D'Andrea, Chris B.; Lampeitl, Hubert; Frieman, Joshua A.; Galbany, Lluís; Garnavich, Peter; Hlozek, Renee; Jha, Saurabh W.; and others

    2014-04-01

    We present the spectroscopy from 5254 galaxies that hosted supernovae (SNe) or other transient events in the Sloan Digital Sky Survey II (SDSS-II). Obtained during SDSS-I, SDSS-II, and the Baryon Oscillation Spectroscopic Survey, this sample represents the largest systematic, unbiased, magnitude limited spectroscopic survey of SN host galaxies. Using the host galaxy redshifts, we test the impact of photometric SN classification based on SDSS imaging data with and without using spectroscopic redshifts of the host galaxies. Following our suggested scheme, there are a total of 1166 photometrically classified SNe Ia when using a flat redshift prior and 1126 SNe Ia when the host spectroscopic redshift is assumed. For 1024 (87.8%) candidates classified as likely SNe Ia without redshift information, we find that the classification is unchanged when adding the host galaxy redshift. Using photometry from SDSS imaging data and the host galaxy spectra, we also report host galaxy properties for use in future analysis of SN astrophysics. Finally, we investigate the differences in the interpretation of the light curve properties with and without knowledge of the redshift. Without host galaxy redshifts, we find that SALT2 light curve fits are systematically biased toward lower photometric redshift estimates and redder colors in the limit of low signal-to-noise data. The general improvements in performance of the light curve fitter and the increased diversity of the host galaxy sample highlights the importance of host galaxy spectroscopy for current photometric SN surveys such as the Dark Energy Survey and future surveys such as the Large Synoptic Survey Telescope.

  14. A PHYSICAL MODEL FOR SN 2001ay, A NORMAL, BRIGHT, EXTREMELY SLOW DECLINING TYPE Ia SUPERNOVA

    SciTech Connect

    Baron, E.; Hoeflich, P.; Krisciunas, K.; Suntzeff, N.; Wang, L.; Dominguez, I.; Phillips, M. M. E-mail: pah@astro.physics.fsu.edu E-mail: suntzeff@physics.tamu.edu E-mail: inma@ugr.es E-mail: mmp@lcoeps1.lco.cl

    2012-07-10

    We present a study of the peculiar Type Ia supernova 2001ay (SN 2001ay). The defining features of its peculiarity are high velocity, broad lines, and a fast rising light curve, combined with the slowest known rate of decline. It is one magnitude dimmer than would be predicted from its observed {Delta}m{sub 15}, and shows broad spectral features. We base our analysis on detailed calculations for the explosion, light curves, and spectra. We demonstrate that consistency is key for both validating the models and probing the underlying physics. We show that this SN can be understood within the physics underlying the {Delta}m{sub 15} relation, and in the framework of pulsating delayed detonation models originating from a Chandrasekhar mass, M{sub Ch}, white dwarf, but with a progenitor core composed of 80% carbon. We suggest a possible scenario for stellar evolution which leads to such a progenitor. We show that the unusual light curve decline can be understood with the same physics as has been used to understand the {Delta}m{sub 15} relation for normal SNe Ia. The decline relation can be explained by a combination of the temperature dependence of the opacity and excess or deficit of the peak luminosity, {alpha}, measured relative to the instantaneous rate of radiative decay energy generation. What differentiates SN 2001ay from normal SNe Ia is a higher explosion energy which leads to a shift of the {sup 56}Ni distribution toward higher velocity and {alpha} < 1. This result is responsible for the fast rise and slow decline. We define a class of SN 2001ay-like SNe Ia, which will show an anti-Phillips relation.

  15. The early phases of the Type Iax supernova SN 2011ay

    NASA Astrophysics Data System (ADS)

    Szalai, Tamás; Vinkó, József; Sárneczky, Krisztián; Takáts, Katalin; Benkő, József M.; Kelemen, János; Kuli, Zoltán; Silverman, Jeffrey M.; Marion, G. Howie; Wheeler, J. Craig

    2015-10-01

    We present a detailed study of the early phases of the peculiar supernova (SN) 2011ay based on BVRI photometry obtained at Konkoly Observatory, Hungary, and optical spectra taken with the Hobby-Eberly Telescope at McDonald Observatory, Texas. The spectral analysis carried out with SYN++ and SYNAPPS confirms that SN 2011ay belongs to the recently defined class of SNe Iax, which is also supported by the properties of its light and colour curves. The estimated photospheric temperature around maximum light, Tphot ˜ 8000 K, is lower than in most SNe Ia, which results in the appearance of strong Fe II features in the spectra of SN 2011ay, even during the early phases. We also show that strong blending with metal features (those of Ti II, Fe II, Co II) makes the direct analysis of the broad spectral features very difficult, and this may be true for all SNe Iax. We find two alternative spectrum models that both describe the observed spectra adequately, but their photospheric velocities differ by at least ˜3000 km s-1. The quasi-bolometric light curve of SN 2011ay has been assembled by integrating the ultraviolet-optical spectral energy distributions. Fitting a modified Arnett model to Lbol(t), the moment of explosion and other physical parameters, i.e. the rise time to maximum, the 56Ni mass and the total ejecta mass are estimated as trise ˜ 14 ± 1 d, MNi ˜ 0.22 ± 0.01 M⊙ and Mej ˜ 0.8 M⊙, respectively.

  16. OGLE-2013-SN-079: A LONELY SUPERNOVA CONSISTENT WITH A HELIUM SHELL DETONATION

    SciTech Connect

    Inserra, C.; Sim, S. A.; Smartt, S. J.; Nicholl, M.; Jerkstrand, A.; Chen, T.-W.; Wyrzykowski, L.; Fraser, M.; Blagorodnova, N.; Campbell, H.; Shen, K. J.; Gal-Yam, A.; Howell, D. A.; Valenti, S.; Maguire, K.; Mazzali, P.; Bersier, D.; Taubenberger, S.; Benitez-Herrera, S.; Elias-Rosa, N.; and others

    2015-01-20

    We present observational data for a peculiar supernova discovered by the OGLE-IV survey and followed by the Public ESO Spectroscopic Survey for Transient Objects. The inferred redshift of z = 0.07 implies an absolute magnitude in the rest-frame I-band of M{sub I} ∼ –17.6 mag. This places it in the luminosity range between normal Type Ia SNe and novae. Optical and near infrared spectroscopy reveal mostly Ti and Ca lines, and an unusually red color arising from strong depression of flux at rest wavelengths <5000 Å. To date, this is the only reported SN showing Ti-dominated spectra. The data are broadly consistent with existing models for the pure detonation of a helium shell around a low-mass CO white dwarf and ''double-detonation'' models that include a secondary detonation of a CO core following a primary detonation in an overlying helium shell.

  17. On the nature of the TeV emission from the supernova remnant SN 1006

    NASA Astrophysics Data System (ADS)

    Araya, Miguel; Frutos, Francisco

    2012-10-01

    We present a model for the non-thermal emission from the historical supernova remnant SN 1006. We constrain the synchrotron parameters of the model with archival radio and hard X-ray data. Our stationary emission model includes two populations of electrons, which is justified by multifrequency images of the object. From the set of parameters that predict the correct synchrotron flux we select those which are able to account, either partly or entirely, for the gamma-ray emission of the source as seen by HESS. We use the results from this model as well as the latest constraints imposed by the Fermi observatory and conclude that the TeV emission cannot be accounted for by π0 decay from high-energy ions with a single power-law distribution, of the form dN proton /dEp∝Ep-s, and s ≳ 2.

  18. Historical Supernovae

    NASA Astrophysics Data System (ADS)

    Green, D. A.; Stephenson, F. R.

    The available historical records of supernovae occurring in our own Galaxy over the past two thousand years are reviewed. These accounts include the well-recorded supernovae of AD1604 (Kepler's SN), AD1572 (Tycho's SN), AD1181 AD1054 (which produced the Crab Nebula) and AD1006, together with less certain events dating back to AD185. In the case of the supernovae of AD1604 and AD1572 it is European records that provide the most accurate information available, whereas for earlier supernovae records are principally from East Asian sources. Also discussed briefly are several spurious supernova candidates, and the future prospects for studies of historical supernovae.

  19. All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin")

    NASA Astrophysics Data System (ADS)

    Shappee, Benjamin; Prieto, J.; Stanek, K. Z.; Kochanek, C. S.; Holoien, T.; Jencson, J.; Basu, U.; Beacom, J. F.; Szczygiel, D.; Pojmanski, G.; Brimacombe, J.; Dubberley, M.; Elphick, M.; Foale, S.; Hawkins, E.; Mullins, D.; Rosing, W.; Ross, R.; Walker, Z.

    2014-01-01

    Even in the modern era, only human eyes scan the entire optical sky for the violent, variable, and transient events that shape our universe. The "All Sky Automated Survey for Supernovae" (ASAS-SN or "Assassin") is changing this by surveying the extragalactic sky roughly once a week, and within a year ASAS-SN will triple in size. We began running our real-time search for variable sources in late April 2013 with our first unit, "Brutus". Brutus presently consists of two telescopes on a common mount hosted by Las Cumbres Observatory Global Telescope Network in the Faulkes Telescope North enclosure on Mount Haleakala, Hawaii. Each telescope consists of a 14-cm Nikon telephoto lens and has a 4.47 by 4.47 degree field-of-view. On a typical clear night, it can survey 5000+ square degrees. The data are reduced in real-time, and we can search for transient candidates about an hour after the data are taken using an automated difference imaging pipeline. We are now meeting, and frequently exceeding, our current depth goal of 16 mag, corresponding to the apparent brightness at maximum light of core-collapse SNe within ~30 Mpc and SNe Ia out to ~100 Mpc. Brutus will shortly expand to have four cameras instead of two, and a second unit, "Cassius", with two cameras, should commence operations in early 2014 on Cerro Tololo, Chile. With these expansions, ASAS-SN will be able to observe the entire extragalactic sky every 2-3 nights. ASAS-SN has already discovered 10+ nearby SNe, 100+ outbursts from CVs and novae, 15+ M-dwarf and other stellar flares, and AGN outbursts which have resulted in 35+ ATel and CBET telegrams and 3 publications. In particular, ASAS-SN discovered one of the most extreme M-dwarf Flares ever detected (delta 9 mag). Furthermore, after triggering on an outburst in NGC 2617 we found that the AGN had changed from a Type 1.8 into a Type 1 Seyfert. After monitoring the transient with Swift and ground-based telescopes for 70 days, we clearly determined that the X

  20. Supernova 2013fc in a circumnuclear ring of a luminous infrared galaxy: the big brother of SN 1998S

    NASA Astrophysics Data System (ADS)

    Kangas, T.; Mattila, S.; Kankare, E.; Lundqvist, P.; Väisänen, P.; Childress, M.; Pignata, G.; McCully, C.; Valenti, S.; Vinkó, J.; Pastorello, A.; Elias-Rosa, N.; Fraser, M.; Gal-Yam, A.; Kotak, R.; Kotilainen, J. K.; Smartt, S. J.; Galbany, L.; Harmanen, J.; Howell, D. A.; Inserra, C.; Marion, G. H.; Quimby, R. M.; Silverman, J. M.; Szalai, T.; Wheeler, J. C.; Ashall, C.; Benetti, S.; Romero-Cañizales, C.; Smith, K. W.; Sullivan, M.; Takáts, K.; Young, D. R.

    2016-02-01

    We present photometric and spectroscopic observations of SN 2013fc, a bright type II supernova (SN) in a circumnuclear star-forming ring in the luminous infrared galaxy ESO 154-G010, observed as part of the Public ESO Spectroscopic Survey of Transient Objects. SN 2013fc is both photometrically and spectroscopically similar to the well-studied type IIn SN 1998S and to the bright type II-L SN 1979C. It exhibits an initial linear decline, followed by a short plateau phase and a tail phase with a decline too fast for 56Co decay with full γ-ray trapping. Initially, the spectrum was blue and featureless. Later on, a strong broad (˜8000 km s-1) H α emission profile became prominent. We apply a STARLIGHT stellar population model fit to the SN location (observed when the SN had faded) to estimate a high extinction of AV = 2.9 ± 0.2 mag and an age of 10_{-2}^{+3} Myr for the underlying cluster. We compare the SN to SNe 1998S and 1979C and discuss its possible progenitor star considering the similarities to these events. With a peak brightness of B = -20.46 ± 0.21 mag, SN 2013fc is 0.9 mag brighter than SN 1998S and of comparable brightness to SN 1979C. We suggest that SN 2013fc was consistent with a massive red supergiant (RSG) progenitor. Recent mass loss probably due to a strong RSG wind created the circumstellar matter illuminated through its interaction with the SN ejecta. We also observe a near-infrared excess, possibly due to newly condensed dust.

  1. SN 2009js AT THE CROSSROADS BETWEEN NORMAL AND SUBLUMINOUS TYPE IIP SUPERNOVAE: OPTICAL AND MID-INFRARED EVOLUTION

    SciTech Connect

    Gandhi, P.; Yamanaka, M.; Itoh, R.; Tanaka, M.; Nozawa, T.; Maeda, K.; Moriya, T. J.; Kawabata, K. S.; Saviane, I.; Hattori, T.; Sasada, M.

    2013-04-20

    We present a study of SN 2009js in NGC 918. Multi-band Kanata optical photometry covering the first {approx}120 days shows the source to be a Type IIP SN. Reddening is dominated by that due to our Galaxy. One-year-post-explosion photometry with the New Technology Telescope and a Subaru optical spectrum 16 days post-discovery both imply a good match with the well-studied subluminous SN 2005cs. The plateau-phase luminosity of SN 2009js and its plateau duration are more similar to the intermediate luminosity IIP SN 2008in. Thus, SN 2009js shares characteristics with both subluminous and intermediate luminosity supernovae (SNe). Its radioactive tail luminosity lies between SN 2005cs and SN 2008in, whereas its quasi-bolometric luminosity decline from peak to plateau (quantified by a newly defined parameter {Delta}logL, which measures adiabatic cooling following shock breakout) is much smaller than both the others'. We estimate the ejected mass of {sup 56}Ni to be low ({approx}0.007 M{sub Sun }). The SN explosion energy appears to have been small, similar to that of SN 2005cs. SN 2009js is the first subluminous SN IIP to be studied in the mid-infrared. It was serendipitously caught by Spitzer at very early times. In addition, it was detected by WISE 105 days later with a significant 4.6 {mu}m flux excess above the photosphere. The infrared excess luminosity relative to the photosphere is clearly smaller than that of SN 2004dj, which has been extensively studied in the mid-infrared. The excess may be tentatively assigned to heated dust with mass {approx}3 Multiplication-Sign 10{sup -5} M{sub Sun }, or to CO fundamental emission as a precursor to dust formation.

  2. The type Iax supernova, SN 2015H. A white dwarf deflagration candidate

    NASA Astrophysics Data System (ADS)

    Magee, M. R.; Kotak, R.; Sim, S. A.; Kromer, M.; Rabinowitz, D.; Smartt, S. J.; Baltay, C.; Campbell, H. C.; Chen, T.-W.; Fink, M.; Gal-Yam, A.; Galbany, L.; Hillebrandt, W.; Inserra, C.; Kankare, E.; Le Guillou, L.; Lyman, J. D.; Maguire, K.; Pakmor, R.; Röpke, F. K.; Ruiter, A. J.; Seitenzahl, I. R.; Sullivan, M.; Valenti, S.; Young, D. R.

    2016-05-01

    We present results based on observations of SN 2015H which belongs to the small group of objects similar to SN 2002cx, otherwise known as type Iax supernovae. The availability of deep pre-explosion imaging allowed us to place tight constraints on the explosion epoch. Our observational campaign began approximately one day post-explosion, and extended over a period of about 150 days post maximum light, making it one of the best observed objects of this class to date. We find a peak magnitude of Mr = -17.27± 0.07, and a (Δm15)r = 0.69 ± 0.04. Comparing our observations to synthetic spectra generated from simulations of deflagrations of Chandrasekhar mass carbon-oxygen white dwarfs, we find reasonable agreement with models of weak deflagrations that result in the ejection of ~0.2 M⊙ of material containing ~0.07 M⊙ of 56Ni. The model light curve however, evolves more rapidly than observations, suggesting that a higher ejecta mass is to be favoured. Nevertheless, empirical modelling of the pseudo-bolometric light curve suggests that ≲0.6 M⊙ of material was ejected, implying that the white dwarf is not completely disrupted, and that a bound remnant is a likely outcome.

  3. Type Ia Supernovae and Their Environment:Theory and Applications to SN 2014J

    NASA Astrophysics Data System (ADS)

    Dragulin, Paul; Hoeflich, Peter

    2016-02-01

    We present theoretical semi-analytic models for the interaction of stellar winds with the interstellar medium (ISM) or prior mass loss implemented in our code SPICE, assuming spherical symmetry and power-law ambient density profiles and using the Π-theorem. This allows us to test a wide variety of configurations, their functional dependencies, and to find classes of solutions for given observations. Here, we study Type Ia Supernova (SN Ia) surroundings of single and double degenerate systems, and their observational signatures. Winds may originate from the progenitor prior to the white dwarf (WD) stage, the WD, a donor star, or an accretion disk (AD). For MCh explosions, the AD wind dominates and produces a low-density void several light years across, surrounded by a dense shell. The bubble explains the lack of observed interaction in late time SN light curves for, at least, several years. The shell produces narrow ISM lines Doppler shifted by 10-100 km s-1, and equivalent widths of ≈100 mÅ and ≈1 mÅ in cases of ambient environments with constant density and produced by prior mass loss, respectively. For SN2014J, both mergers and MCh mass explosions have been suggested based on radio and narrow lines. As a consistent and most likely solution, we find an AD wind running into an environment produced by the red giant wind of the progenitor during the pre-WD stage, and a short delay, 0.013-1.4 Myr, between the WD formation and the explosion. Our framework may be applied more generally to stellar winds and star formation feedback in large scale galactic evolution simulations.

  4. Gamma-ray observations of supernova SN1987A by the balloonborne gamma-ray advanced detector

    SciTech Connect

    Coldwell, R.L.; Rester, A.C. ); Eichhorn, G. ); Starr, R.; Trombka, J.I. ); Lasche, G.P. )

    1988-01-01

    On 8 January 1988, gamma-ray advanced detector (GRAD) supernova observer was launched on a 3.3 x 10{sup 5} cubic meter helium balloon from Williams Field. The instrument maintained a float altitude of 36 kilometers as it drifted eastward along the 78{degrees}S parallel until it was brought down 320 kilometers east of Vostak Station on 10 January and recovered on 13 January. High-energy resolution gamma-ray spectra of the supernova SN1987A were taken; it is hoped that these spectra will provide evidence of explosive nucleosynthesis of the heavy elements in the supernova. Results. The earliest results of the analysis, showed evidence of gamma rays from the radioactive decay of the isotope cobalt-56, the longer-lived daughter of short-lived nickel-56, which was expected to be produced in great abundance in the supernova explosion, but the cobalt-56 line appearing most clearly in the supernova spectrum-the 1,238-kiloelectronvolt gamma-ray--was apparently split into two doppler-shifted and broadened components. This astonishing result appeared to suggest that the mantle of the supernova had expanded asymmetrically with a velocity in excess of 3,000 kilometers per second.

  5. SN 2011dh: DISCOVERY OF A TYPE IIb SUPERNOVA FROM A COMPACT PROGENITOR IN THE NEARBY GALAXY M51

    SciTech Connect

    Arcavi, Iair; Gal-Yam, Avishay; Yaron, Ofer; Sternberg, Assaf; Rabinak, Itay; Waxman, Eli; Kasliwal, Mansi M.; Quimby, Robert M.; Ofek, Eran O.; Horesh, Assaf; Kulkarni, Shrinivas R.; Filippenko, Alexei V.; Silverman, Jeffrey M.; Cenko, S. Bradley; Li, Weidong; Bloom, Joshua S.; Nugent, Peter E.; Poznanski, Dovi; Sullivan, Mark; Gorbikov, Evgeny; and others

    2011-12-15

    On 2011 May 31 UT a supernova (SN) exploded in the nearby galaxy M51 (the Whirlpool Galaxy). We discovered this event using small telescopes equipped with CCD cameras and also detected it with the Palomar Transient Factory survey, rapidly confirming it to be a Type II SN. Here, we present multi-color ultraviolet through infrared photometry which is used to calculate the bolometric luminosity and a series of spectra. Our early-time observations indicate that SN 2011dh resulted from the explosion of a relatively compact progenitor star. Rapid shock-breakout cooling leads to relatively low temperatures in early-time spectra, compared to explosions of red supergiant stars, as well as a rapid early light curve decline. Optical spectra of SN 2011dh are dominated by H lines out to day 10 after explosion, after which He I lines develop. This SN is likely a member of the cIIb (compact IIb) class, with progenitor radius larger than that of SN 2008ax and smaller than the eIIb (extended IIb) SN 1993J progenitor. Our data imply that the object identified in pre-explosion Hubble Space Telescope images at the SN location is possibly a companion to the progenitor or a blended source, and not the progenitor star itself, as its radius ({approx}10{sup 13} cm) would be highly inconsistent with constraints from our post-explosion spectra.

  6. ASAS-SN Discovery of Two Probable Supernovae in CGCG 257-002 and SDSS J145027.61+063713.3

    NASA Astrophysics Data System (ADS)

    Nicolas, J.; Kiyota, S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Brimacombe, J.; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Fernandez, J. M.; Koff, R. A.; Masi, G.; Monard, L. A. G.; Nicholls, B.

    2015-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered two new transient sources, most likely supernovae, in the galaxies CGCG 257-002 and SDSS J145027.61+063713.3.

  7. SALT spectroscopic classification of PS16efm (= SN 2016fxu) as a type-Ic supernova after maximum light

    NASA Astrophysics Data System (ADS)

    Jha, S. W.; Dettman, K.; Pan, Y.-C.; Foley, R. J.; Rest, A.; Scolnic, D.; Kotze, M.

    2016-09-01

    We obtained SALT (+RSS) spectroscopy of PS16efm (= SN 2016fxu) on 2016 Sep 8.0 UT, covering the wavelength range 350-920 nm. Cross-correlation of the spectrum with a template library using SNID (Blondin & Tonry 2007, ApJ, 666, 1024) shows PS16efm is a type-Ic supernova approximately two to three weeks past maximum light.

  8. Abundance stratification in Type Ia supernovae - V. SN 1986G bridging the gap between normal and subluminous SNe Ia

    NASA Astrophysics Data System (ADS)

    Ashall, C.; Mazzali, P. A.; Pian, E.; James, P. A.

    2016-08-01

    A detailed spectroscopic analysis of SN 1986G has been performed. SN 1986G `bridges the gap' between normal and sub luminous type Ia supernova (SNe Ia). The abundance tomography technique is used to determine the abundance distribution of the elements in the ejecta. SN 1986G was found to be a low energy Chandrasekhar mass explosion. Its kinetic energy was 70% of the standard W7 model (0.9 × 1051 erg). Oxygen dominates the ejecta from the outermost layers down to ˜ 9000 kms-1 , intermediate mass elements (IME) dominate from ˜ 9000 kms-1 to ˜ 3500 kms-1 with Ni and Fe dominating the inner layers <˜ 3500 kms-1. The final masses of the main elements in the ejecta were found to be, O=0.33 M⊙, IME=0.69 M⊙, stable NSE=0.21 M⊙, 56Ni=0.14 M⊙. An upper limit of the carbon mass is set at C=0.02 M⊙. The spectra of SN 1986G consist of almost exclusively singly ionised species. SN 1986G can be thought of as a low luminosity extension of the main population of SN Ia, with a large deflagration phase that produced more IMEs than a standard SN Ia.

  9. Late-time Photometry of Type Ia Supernova SN 2012cg Reveals the Radioactive Decay of 57 Co

    NASA Astrophysics Data System (ADS)

    Graur, Or; Zurek, David; Shara, Michael M.; Riess, Adam G.; Seitenzahl, Ivo R.; Rest, Armin

    2016-03-01

    Seitenzahl et al. have predicted that roughly three years after its explosion, the light we receive from a Type Ia supernova (SN Ia) will come mostly from reprocessing of electrons and X-rays emitted by the radioactive decay chain 57Co → 57Fe, instead of positrons from the decay chain 56Co → 56Fe that dominates the SN light at earlier times. Using the Hubble Space Telescope, we followed the light curve of the SN Ia SN 2012cg out to 1055 days after maximum light. Our measurements are consistent with the light curves predicted by the contribution of energy from the reprocessing of electrons and X-rays emitted by the decay of 57Co, offering evidence that 57Co is produced in SN Ia explosions. However, the data are also consistent with a light echo ∼14 mag fainter than SN 2012cg at peak. Assuming no light-echo contamination, the mass ratio of 57Ni and 56Ni produced by the explosion, a strong constraint on any SN Ia explosion models, is {0.043}-0.011+0.012, roughly twice Solar. In the context of current explosion models, this value favors a progenitor white dwarf with a mass near the Chandrasekhar limit.

  10. SN 2015BN: A Detailed Multi-wavelength View of a Nearby Superluminous Supernova

    NASA Astrophysics Data System (ADS)

    Nicholl, M.; Berger, E.; Smartt, S. J.; Margutti, R.; Kamble, A.; Alexander, K. D.; Chen, T.-W.; Inserra, C.; Arcavi, I.; Blanchard, P. K.; Cartier, R.; Chambers, K. C.; Childress, M. J.; Chornock, R.; Cowperthwaite, P. S.; Drout, M.; Flewelling, H. A.; Fraser, M.; Gal-Yam, A.; Galbany, L.; Harmanen, J.; Holoien, T. W.-S.; Hosseinzadeh, G.; Howell, D. A.; Huber, M. E.; Jerkstrand, A.; Kankare, E.; Kochanek, C. S.; Lin, Z.-Y.; Lunnan, R.; Magnier, E. A.; Maguire, K.; McCully, C.; McDonald, M.; Metzger, B. D.; Milisavljevic, D.; Mitra, A.; Reynolds, T.; Saario, J.; Shappee, B. J.; Smith, K. W.; Valenti, S.; Villar, V. A.; Waters, C.; Young, D. R.

    2016-07-01

    We present observations of SN 2015bn (=PS15ae = CSS141223-113342+004332 = MLS150211-113342+004333), a Type I superluminous supernova (SLSN) at redshift z = 0.1136. As well as being one of the closest SLSNe I yet discovered, it is intrinsically brighter ({M}U≈ -23.1) and in a fainter galaxy ({M}B≈ -16.0) than other SLSNe at z∼ 0.1. We used this opportunity to collect the most extensive data set for any SLSN I to date, including densely sampled spectroscopy and photometry, from the UV to the NIR, spanning ‑50 to +250 days from optical maximum. SN 2015bn fades slowly, but exhibits surprising undulations in the light curve on a timescale of 30–50 days, especially in the UV. The spectrum shows extraordinarily slow evolution except for a rapid transformation between +7 and +20–30 days. No narrow emission lines from slow-moving material are observed at any phase. We derive physical properties including the bolometric luminosity, and find slow velocity evolution and non-monotonic temperature and radial evolution. A deep radio limit rules out a healthy off-axis gamma-ray burst, and places constraints on the pre-explosion mass loss. The data can be consistently explained by a ≳ 10 M {}ȯ stripped progenitor exploding with ∼ {10}51 erg kinetic energy, forming a magnetar with a spin-down timescale of ∼20 days (thus avoiding a gamma-ray burst) that reheats the ejecta and drives ionization fronts. The most likely alternative scenario—interaction with ∼20 M {}ȯ of dense, inhomogeneous circumstellar material—can be tested with continuing radio follow-up.

  11. SN 2015BN: A Detailed Multi-wavelength View of a Nearby Superluminous Supernova

    NASA Astrophysics Data System (ADS)

    Nicholl, M.; Berger, E.; Smartt, S. J.; Margutti, R.; Kamble, A.; Alexander, K. D.; Chen, T.-W.; Inserra, C.; Arcavi, I.; Blanchard, P. K.; Cartier, R.; Chambers, K. C.; Childress, M. J.; Chornock, R.; Cowperthwaite, P. S.; Drout, M.; Flewelling, H. A.; Fraser, M.; Gal-Yam, A.; Galbany, L.; Harmanen, J.; Holoien, T. W.-S.; Hosseinzadeh, G.; Howell, D. A.; Huber, M. E.; Jerkstrand, A.; Kankare, E.; Kochanek, C. S.; Lin, Z.-Y.; Lunnan, R.; Magnier, E. A.; Maguire, K.; McCully, C.; McDonald, M.; Metzger, B. D.; Milisavljevic, D.; Mitra, A.; Reynolds, T.; Saario, J.; Shappee, B. J.; Smith, K. W.; Valenti, S.; Villar, V. A.; Waters, C.; Young, D. R.

    2016-07-01

    We present observations of SN 2015bn (=PS15ae = CSS141223-113342+004332 = MLS150211-113342+004333), a Type I superluminous supernova (SLSN) at redshift z = 0.1136. As well as being one of the closest SLSNe I yet discovered, it is intrinsically brighter ({M}U≈ -23.1) and in a fainter galaxy ({M}B≈ -16.0) than other SLSNe at z˜ 0.1. We used this opportunity to collect the most extensive data set for any SLSN I to date, including densely sampled spectroscopy and photometry, from the UV to the NIR, spanning ‑50 to +250 days from optical maximum. SN 2015bn fades slowly, but exhibits surprising undulations in the light curve on a timescale of 30–50 days, especially in the UV. The spectrum shows extraordinarily slow evolution except for a rapid transformation between +7 and +20–30 days. No narrow emission lines from slow-moving material are observed at any phase. We derive physical properties including the bolometric luminosity, and find slow velocity evolution and non-monotonic temperature and radial evolution. A deep radio limit rules out a healthy off-axis gamma-ray burst, and places constraints on the pre-explosion mass loss. The data can be consistently explained by a ≳ 10 M {}ȯ stripped progenitor exploding with ˜ {10}51 erg kinetic energy, forming a magnetar with a spin-down timescale of ˜20 days (thus avoiding a gamma-ray burst) that reheats the ejecta and drives ionization fronts. The most likely alternative scenario—interaction with ˜20 M {}ȯ of dense, inhomogeneous circumstellar material—can be tested with continuing radio follow-up.

  12. The Supernova Spectropolarimetry Project: Results from Multi-Epoch Observations of the Type IIb SN 2011dh

    NASA Astrophysics Data System (ADS)

    Bilinski, Christopher; Williams, G. G.; Smith, P. S.; Smith, N.; Milne, P.; Hoffman, J. L.; Huk, L. N.; Leonard, D. C.; Dessart, L.

    2014-01-01

    The Supernova Spectropolarimetry Project is a recently formed collaboration between observers and theorists that focuses on decoding the complex, time-dependent spectropolarimetric behavior of supernovae (SNe) of all types. Using the CCD Imaging/Spectropolarimeter (SPOL) at the 61" Kuiper, the 90" Bok, and the 6.5-m MMT telescopes, we obtain multi-epoch observations of each target, aiming to construct the most comprehensive survey to date of supernovae in polarized light. Preliminary results from the SNSPOL project provide support for the increasingly popular hypothesis that many supernovae are aspherical explosion events. Thus far, we have observed 27 different SNe, many over multiple epochs, over the course of the last three years. While the history and evolution of these events is often studied with photometric and spectroscopic information, most supernovae are not studied with the combined advantage that spectropolarimetric data provides. The use of polarimetry allows us to probe the extent of the asphericity of the explosions while the use of spectroscopy allows us to characterize this asphericity across a variety of chemical species individually and as a function of velocity. Modern 3-D model simulations favor an explosion mechanism that is often inherently asymmetric in nature. Here, we showcase some of our initial results for the nearby type-IIb SN 2011dh that demonstrate the unique information that spectropolarimetric observations provide.

  13. The Supernova Spectropolarimetry Project: Results from Multi-Epoch Observations of the Type IIn SN 2010jl

    NASA Astrophysics Data System (ADS)

    Williams, George G.; Dessart, L.; Hoffman, J. L.; Huk, L. N.; Leonard, D. C.; Milne, P.; Smith, N.; Smith, P. S.

    2014-01-01

    The Supernova Spectropolarimetry Project is a recently formed collaboration between observers and theorists that focuses on decoding the complex, time-dependent spectropolarimetric behavior of supernovae (SNe) of all types. Using the CCD Imaging/Spectropolarimeter (SPOL) at the 61" Kuiper, the 90" Bok, and the 6.5-m MMT telescopes, we obtain multi-epoch observations of each target, aiming to construct the most comprehensive survey to date of supernovae in polarized light. We present results from the multi-epoch spectropolarimetric observations of the SN 2010jl. This type IIn supernova in UGC 5189A remained bright for an unusually long time allowing us to obtain 11 epochs of data over the course of 15 months. We find significant polarization in the continuum and variations in polarization across the Balmer and HeI lines. The measured polarized continuum decreased steadily over the 15 months of observations. This evolution allowed us to make a solid estimate of the interstellar polarization component thereby revealing the intrinsic supernova polarization. The polarization provides us with detailed information about the aspherical morphology of the explosion and the properties of the progenitor’s pre-explosion mass loss.

  14. Supernova 1987A in the Large Magellanic Cloud; Proceedings of the Fourth George Mason Astrophysics Workshop, George Mason University, Fairfax, VA, Oct. 12-14, 1987

    NASA Technical Reports Server (NTRS)

    Kafatos, Minas (Editor); Michalitsianos, Andrew G. (Editor)

    1988-01-01

    Papers concerning SN 1987A are presented, covering topics such as images and spectrograms of the SN 1987A progenitor, a linear polarimetric study of SN 1987A, the energetics, nature, and uniqueness of the supernova, comparison of the SN 1987A light curve with other type II supernovae, P-Cygni features and photospheric velocities, the neutrino burst from SN 1987A, mass determination of neutrinos, neutrino transport, energetics, and oscillations. Additional papers discuss supernovae light echoes, the UV interstellar spectrum of SN 1987A, theoretical models of SN 1987A, circumstellar and interstellar interaction, the supernova as a stripped asymptotic-branch giant in a binary system, pulsar formation and the fall back mass fraction, the signals of particle acceleration at SN 1987A, the effects of the mixing of the ejecta on the hard X-ray emissions from the supernova, possible s-process gamma-ray lines in supernovae, detectability of early thermal radiation from a neutron star in SN 1987A, NASA studies of the supernova, and information exchange for SN 1987A. Observational studies presented include optical, IR, radio, and UV observations, IR speckle-interferometry, coded mask X-ray observations, broad band X-ray imaging spectrophotometry, gamma-ray and thermal X-ray observations, and reports from several observatories.

  15. SN 2007bg: the complex circumstellar medium around one of the most radio-luminous broad-lined Type Ic supernovae

    NASA Astrophysics Data System (ADS)

    Salas, P.; Bauer, F. E.; Stockdale, C.; Prieto, J. L.

    2013-01-01

    In this paper we present the results of the radio light curve and X-ray observations of broad-lined Type Ic (Ic-BL) SN 2007bg. The light curve shows three distinct phases of spectral and temporal evolution, implying that the supernova (SN) shock likely encountered at least three different circumstellar medium regimes. We interpret this as the progenitor of SN 2007bg having at least two distinct mass-loss episodes (i.e. phases 1 and 3) during its final stages of evolution, yielding a highly stratified circumstellar medium. Modelling the phase 1 light curve as a freely expanding, synchrotron-emitting shell, self-absorbed by its own radiating electrons, requires a progenitor mass-loss rate of skew4dot{M}≈ 1.9× 10^{-6}(v_w/1000 km s^{-1}) M⊙ yr-1 for the last t ˜ 20(vw/1000 km s-1) yr before explosion and a total energy of the radio-emitting ejecta of E ≈ 1 × 1048 erg 10 d after explosion. This places SN 2007bg among the most energetic Type Ib/c events. We interpret the second phase as a sparser `gap' region between the two winds stages. Phase 3 shows a second absorption turn-on before rising to a peak luminosity 2.6 times higher than in phase 1. Assuming this luminosity jump is due to a circumstellar medium density enhancement from a faster previous mass-loss episode, we estimate that the phase 3 mass-loss rate could be as high as skew4dot{M}lesssim 4.3× 10^{-4}(v_w/1000 km s^{-1}) M⊙ yr-1. The phase 3 wind would have transitioned directly into the phase 1 wind for a wind speed difference of ≈2. In summary, the radio light curve provides robust evidence for dramatic global changes in at least some Ic-BL progenitors just prior (˜10-1000 yr) to explosion. The observed luminosity of this SN is the highest observed for a non-gamma-ray-burst Ic-BL SN, reaching L8.46 GHz ≈ 1 × 1029 erg Hz-1 s-1, ˜567 d after explosion.

  16. A SWIFT LOOK AT SN 2011fe: THE EARLIEST ULTRAVIOLET OBSERVATIONS OF A TYPE Ia SUPERNOVA

    SciTech Connect

    Brown, Peter J.; Dawson, Kyle S.; De Pasquale, Massimiliano; Gronwall, Caryl; Siegel, Michael; Holland, Stephen; Immler, Stefan; Kuin, Paul; Oates, Samantha; Mazzali, Paolo; Milne, Peter

    2012-07-01

    We present the earliest ultraviolet (UV) observations of the bright Type Ia supernova SN 2011fe/PTF11kly in the nearby galaxy M101 at a distance of only 6.4 Mpc. It was discovered shortly after explosion by the Palomar Transient Factory and first observed by Swift/UVOT about a day after explosion. The early UV light is well defined, with {approx}20 data points per filter in the five days after explosion. These early and well-sampled UV observations form new template light curves for comparison with observations of other SNe Ia at low and high redshift. We report fits from semiempirical models of the explosion and find the time evolution of the early UV flux to be well fitted by the superposition of two parabolic curves. Finally, we use the early UV flux measurements to examine a possible shock interaction with a non-degenerate companion. From models predicting the measurable shock emission, we find that even a solar mass companion at a distance of a few solar radii is unlikely at more than 95% confidence.

  17. A Swift Look at SN 2011fe: The Earliest Ultraviolet Observations of a Type Ia Supernova

    NASA Technical Reports Server (NTRS)

    Oates, Samantha; Holland, Stephen; Immler, Stefan; Brown, Peter J.; Dawson, Kyle S.; DePasquale, Massimiliano; Gronwall, Caryl; Kuin, Paul; Mazzali, Paolo; Miline, Peter; Siegel, Michael

    2012-01-01

    We present the earliest ultraviolet (UV) observations of the bright Type Ia supernova SN 2011fe/PTF11kly in the nearby galaxy M101 at a distance of only 6.4 Mpc. It was discovered shortly after explosion by the Palomar Transient Factory and first observed by Swift/UVOT about a day after explosion. The early UV light is well-defined, with approx. 20 data points per filter in the 5 days after explosion. With these early UV observations, we extend the near-UV template of SNe Ia to earlier times for comparison with observations at low and high redshift and report fits from semiempirical models of the explosion. We find the early UV count rates to be well fit by the superposition of two parabolic curves. Finally, we use the early UV flux measurements to examine a possible shock interaction with a non-degenerate companion. We find that even a solar mass companion at a distance of a few solar radii is unlikely at more than 95% confidence.

  18. Re-examination of the Expected Gamma-Ray Emission of Supernova Remnant SN 1987A

    NASA Astrophysics Data System (ADS)

    Berezhko, E. G.; Ksenofontov, L. T.; Völk, H. J.

    2015-09-01

    A nonlinear kinetic theory, combining cosmic-ray (CR) acceleration in supernova remnants (SNRs) with their gas dynamics, is used to re-examine the nonthermal properties of the remnant of SN 1987A for an extended evolutionary period of 5-50 year. This spherically symmetric model is approximately applied to the different features of the SNR, consisting of (i) a blue supergiant wind and bubble, and (ii) of the swept-up red supergiant (RSG) wind structures in the form of an H ii region, an equatorial ring (ER), and an hourglass region. The RSG wind involves a mass loss rate that decreases significantly with elevation above and below the equatorial plane. The model adapts recent three-dimensional hydrodynamical simulations by Potter et al. in 2014 that use a significantlysmaller ionized mass of the ER than assumed in the earlier studies by the present authors. The SNR shock recently swept up the ER, which is the densest region in the immediate circumstellar environment. Therefore, the expected gamma-ray energy flux density at TeV energies in the current epoch has already reached its maximal value of ˜10-13 erg cm-2 s-1. This flux should decrease by a factor of about two over the next 10 years.

  19. The behavior of supernova SN 2014cy in the optical wavelength

    NASA Astrophysics Data System (ADS)

    Singh, Mridweeka

    2016-07-01

    The supernovae (SNe) of type II prominently exhibit presence of hydrogen in their early spectra and are results of the core collapse of massive stars. These SNe show a wide variety of light curve and spectral properties. A detailed analysis of individual SNe allows us to study the peculiarities seen in the different sub-classes of type II SNe. In this poster we present the optical observations of a type IIP SN 2014cy which occurred in the galaxy NGC 7742. High cadence photometric observations, covering a span of ~150 days, were taken with the 1.0m class telescopes at ARIES. Supplementary spectroscopic observations were taken with the 2.0m Himalayan Chandra Telescope at IAO, Hanle. The light curve evolution in different phases allows us to estimate various physical parameters such as the Ni mass, ejected mass and progenitor mass. We also present a comparison of the physical properties of a sample of other well studied type IIP SNe.

  20. SN 2010mb: Direct evidence for a supernova interacting with a large amount of hydrogen-free circumstellar material

    SciTech Connect

    Ben-Ami, Sagi; Gal-Yam, Avishay; Rabinak, Itay; Yaron, Ofer; Arcavi, Iair; Ofek, Eran O.; Mazzali, Paolo A.; Gnat, Orly; Modjaz, Maryam; Sullivan, Mark; Bildsten, Lars; Poznanski, Dovi; Bloom, Joshua S.; Nugent, Peter E.; Horesh, Assaf; Kulkarni, Shrinivas R.; Perley, Daniel; Kasliwal, Mansi M.; Quimby, Robert; Xu, Dong

    2014-04-10

    We present our observations of SN 2010mb, a Type Ic supernova (SN) lacking spectroscopic signatures of H and He. SN 2010mb has a slowly declining light curve (LC) (∼600 days) that cannot be powered by {sup 56}Ni/{sup 56}Co radioactivity, the common energy source for Type Ic SNe. We detect signatures of interaction with hydrogen-free circumstellar material including a blue quasi-continuum and, uniquely, narrow oxygen emission lines that require high densities (∼10{sup 9} cm{sup –3}). From the observed spectra and LC, we estimate that the amount of material involved in the interaction was ∼3 M {sub ☉}. Our observations are in agreement with models of pulsational pair-instability SNe described in the literature.

  1. Progenitors of Type IIB Supernovae in the Light of Radio and X-Rays from SN 2013DF

    NASA Astrophysics Data System (ADS)

    Kamble, Atish; Margutti, Raffaella; Soderberg, Alicia M.; Chakraborti, Sayan; Fransson, Claes; Chevalier, Roger; Powell, Diana; Milisavljevic, Dan; Parrent, Jerod; Bietenholz, Michael

    2016-02-01

    We present radio and X-ray observations of the nearby SN IIb 2013df in NGC 4414 from 10 to 250 days after the explosion. The radio emission showed a peculiar steep-to-shallow spectral evolution. We present a model in which inverse Compton cooling of synchrotron emitting electrons can account for the observed spectral and light curve evolution. A significant mass-loss rate, \\dot{M}≈ 8× {10}-5 {M}⊙ yr-1 for a wind velocity of 10 km s-1, is estimated from the detailed modeling of radio and X-ray emission, which are primarily due to synchrotron and bremsstrahlung, respectively. We show that SN 2013df is similar to SN 1993J in various ways. The shock wave speed of SN 2013df was found to be average among the radio supernovae; {v}{sh}/c˜ 0.07. We did not find any significant deviation from smooth decline in the light curve of SN 2013df. One of the main results of our self-consistent multiband modeling is the significant deviation from energy equipartition between magnetic fields and relativistic electrons behind the shock. We estimate {ɛ }e=200{ɛ }B. In general for SNe IIb, we find that the presence of bright optical cooling envelope emission is linked with free-free radio absorption and bright thermal X-ray emission. This finding suggests that more extended progenitors, similar to that of SN 2013df, suffer from substantial mass loss in the years before the supernova.

  2. A trio of gamma-ray burst supernovae:. GRB 120729A, GRB 130215A/SN 2013ez, and GRB 130831A/SN 2013fu

    NASA Astrophysics Data System (ADS)

    Cano, Z.; de Ugarte Postigo, A.; Pozanenko, A.; Butler, N.; Thöne, C. C.; Guidorzi, C.; Krühler, T.; Gorosabel, J.; Jakobsson, P.; Leloudas, G.; Malesani, D.; Hjorth, J.; Melandri, A.; Mundell, C.; Wiersema, K.; D'Avanzo, P.; Schulze, S.; Gomboc, A.; Johansson, A.; Zheng, W.; Kann, D. A.; Knust, F.; Varela, K.; Akerlof, C. W.; Bloom, J.; Burkhonov, O.; Cooke, E.; de Diego, J. A.; Dhungana, G.; Farina, C.; Ferrante, F. V.; Flewelling, H. A.; Fox, O. D.; Fynbo, J.; Gehrels, N.; Georgiev, L.; González, J. J.; Greiner, J.; Güver, T.; Hartoog, O.; Hatch, N.; Jelinek, M.; Kehoe, R.; Klose, S.; Klunko, E.; Kopač, D.; Kutyrev, A.; Krugly, Y.; Lee, W. H.; Levan, A.; Linkov, V.; Matkin, A.; Minikulov, N.; Molotov, I.; Prochaska, J. X.; Richer, M. G.; Román-Zúñiga, C. G.; Rumyantsev, V.; Sánchez-Ramírez, R.; Steele, I.; Tanvir, N. R.; Volnova, A.; Watson, A. M.; Xu, D.; Yuan, F.

    2014-08-01

    We present optical and near-infrared (NIR) photometry for three gamma-ray burst supernovae (GRB-SNe): GRB 120729A, GRB 130215A/SN 2013ez, and GRB 130831A/SN 2013fu. For GRB 130215A/SN 2013ez, we also present optical spectroscopy at t - t0 = 16.1 d, which covers rest-frame 3000-6250 Å. Based on Fe ii λ5169 and Si ii λ6355, our spectrum indicates an unusually low expansion velocity of ~4000-6350 km s-1, the lowest ever measured for a GRB-SN. Additionally, we determined the brightness and shape of each accompanying SN relative to a template supernova (SN 1998bw), which were used to estimate the amount of nickel produced via nucleosynthesis during each explosion. We find that our derived nickel masses are typical of other GRB-SNe, and greater than those of SNe Ibc that are not associated with GRBs. For GRB 130831A/SN 2013fu, we used our well-sampled R-band light curve (LC) to estimate the amount of ejecta mass and the kinetic energy of the SN, finding that these too are similar to other GRB-SNe. For GRB 130215A, we took advantage of contemporaneous optical/NIR observations to construct an optical/NIR bolometric LC of the afterglow. We fit the bolometric LC with the millisecond magnetar model of Zhang & Mészáros (2001, ApJ, 552, L35), which considers dipole radiation as a source of energy injection to the forward shock powering the optical/NIR afterglow. Using this model we derive an initial spin period of P = 12 ms and a magnetic field of B = 1.1 × 1015 G, which are commensurate with those found for proposed magnetar central engines of other long-duration GRBs. Table 3 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/568/A19

  3. Early Radio and X-Ray Observations of the Youngest Nearby Type Ia Supernova PTF 11kly (SN 2011fe)

    NASA Technical Reports Server (NTRS)

    Horesh, Assaf; Kulkarni, S. R.; Fox, Derek B.; Carpenter, John; Kasliwal, Mansi M.; Ofek, Eran O.; Quimby, Robert; Gal-Yam, Avishay; Cenko, S. Bradley; deBruyn, A. G.; Kamble, Atish; Wijers, Ralph A. M. J.; vanderHorst, Alexander J.; Kouveliotou, Chryssa; Podsiadlowski, Philipp; Sullivan, Mark; Maguire, Kate; Howell, D. Andrew; Nugent, Peter E.; Gehrels, Neil; Law, Nicolas M.; Poznanski, Dovi; Shara, Michael

    2012-01-01

    On August 24 (UT) the Palomar Transient Factory (PTF) discovered PTF11kly (SN 2011fe), the youngest and most nearby type Ia supernova (SN Ia) in decades. We followed this event up in the radio (centimeter and millimeter bands) and X-ray bands, starting about a day after the estimated explosion time. We present our analysis of the radio and X-ray observations, yielding the tightest constraints yet placed on the pre-explosion mass-loss rate from the progenitor system of this supernova. We find a robust limit of M(raised dot) less than or equal to 10(exp -8) (w /100 kilometers per second ) solar mass yr(exp -1) from sensitive X-ray non-detections, as well as a similar limit from radio data, which depends, however, on assumptions about microphysical parameters. We discuss our results in the context of single-degenerate models for SNe Ia and find that our observations modestly disfavor symbiotic progenitor models involving a red giant donor, but cannot constrain systems accreting from main sequence or sub-giant stars, including the popular supersoft channel. In view of the proximity of PTF11kly and the sensitivity of our prompt observations we would have to wait for a long time (decade or longer) in order to more meaningfully probe the circumstellar matter of Ia supernovae.

  4. Exclusion of a luminous red giant as a companion star to the progenitor of supernova SN 2011fe.

    PubMed

    Li, Weidong; Bloom, Joshua S; Podsiadlowski, Philipp; Miller, Adam A; Cenko, S Bradley; Jha, Saurabh W; Sullivan, Mark; Howell, D Andrew; Nugent, Peter E; Butler, Nathaniel R; Ofek, Eran O; Kasliwal, Mansi M; Richards, Joseph W; Stockton, Alan; Shih, Hsin-Yi; Bildsten, Lars; Shara, Michael M; Bibby, Joanne; Filippenko, Alexei V; Ganeshalingam, Mohan; Silverman, Jeffrey M; Kulkarni, S R; Law, Nicholas M; Poznanski, Dovi; Quimby, Robert M; McCully, Curtis; Patel, Brandon; Maguire, Kate; Shen, Ken J

    2011-12-15

    Type Ia supernovae are thought to result from a thermonuclear explosion of an accreting white dwarf in a binary system, but little is known of the precise nature of the companion star and the physical properties of the progenitor system. There are two classes of models: double-degenerate (involving two white dwarfs in a close binary system) and single-degenerate models. In the latter, the primary white dwarf accretes material from a secondary companion until conditions are such that carbon ignites, at a mass of 1.38 times the mass of the Sun. The type Ia supernova SN 2011fe was recently detected in a nearby galaxy. Here we report an analysis of archival images of the location of SN 2011fe. The luminosity of the progenitor system (especially the companion star) is 10-100 times fainter than previous limits on other type Ia supernova progenitor systems, allowing us to rule out luminous red giants and almost all helium stars as the mass-donating companion to the exploding white dwarf. PMID:22170681

  5. Supernova VLBI

    NASA Astrophysics Data System (ADS)

    Bartel, N.

    2009-08-01

    We review VLBI observations of supernovae over the last quarter century and discuss the prospect of imaging future supernovae with space VLBI in the context of VSOP-2. From thousands of discovered supernovae, most of them at cosmological distances, ˜50 have been detected at radio wavelengths, most of them in relatively nearby galaxies. All of the radio supernovae are Type II or Ib/c, which originate from the explosion of massive progenitor stars. Of these, 12 were observed with VLBI and four of them, SN 1979C, SN 1986J, SN 1993J, and SN 1987A, could be imaged in detail, the former three with VLBI. In addition, supernovae or young supernova remnants were discovered at radio wavelengths in highly dust-obscured galaxies, such as M82, Arp 299, and Arp 220, and some of them could also be imaged in detail. Four of the supernovae so far observed were sufficiently bright to be detectable with VSOP-2. With VSOP-2 the expansion of supernovae can be monitored and investigated with unsurpassed angular resolution, starting as early as the time of the supernova's transition from its opaque to transparent stage. Such studies can reveal, in a movie, the aftermath of a supernova explosion shortly after shock break out.

  6. Revised Lens Model for the Multiply Imaged Lensed Supernova, “SN Refsdal” in MACS J1149+2223

    NASA Astrophysics Data System (ADS)

    Sharon, Keren; Johnson, Traci L.

    2015-02-01

    We present a revised lens model of MACS J1149+2223, in which the first resolved multiply imaged lensed supernova (SN) was discovered. The lens model is based on the model of Johnson et al. with some modifications. We include more lensing constraints from the host galaxy of the newly discovered SN, and increase the flexibility of the model in order to better reproduce the lensing signal in the vicinity of this galaxy. The revised model accurately reconstructs the positions of the lensed SN, provides magnifications, and predicts the time delay between the instances of the SN. Finally, we reconstruct the source image of the host galaxy, and position the SN on one of its spiral arms. Products of this lens model are available to the community through MAST. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs GO 9722, GO 12065.

  7. Spectral Models of the Type IC Supernova SN 1994I in M51

    NASA Astrophysics Data System (ADS)

    Baron, E.; Branch, David; Hauschildt, Peter H.; Filippenko, Alexei V.; Kirshner, R. P.

    1999-12-01

    We present detailed non-LTE (NLTE) synthetic spectra for comparison with a time series of observed optical spectra of the Type Ic supernova SN 1994I which occurred in M51. With the exceptions of Si I and S I, we treat the important species in the formation of the spectrum in full NLTE. We present results for both a hydrodynamic model that has been fitted to the light curve and for an illustrative custom-crafted model that is more massive. Both models give reasonable fits to the overall observed spectra; however, neither is able to reproduce all the observed features. Some conspicuous observed features are absent, and some predicted features are unobserved. No model that we have explored is able to reproduce satisfactorily the observed infrared feature near 1 μm on 1994 April 15 (+7 days), which has been attributed to the triplet He I λ10830 transition. The low-mass hydrodynamic model produces an infrared feature with a blend of He I, C I, O I, and Si I-Si II lines, but it predicts a strong unobserved absorption feature near 6100 Å due to Fe III, and the observed feature just blueward of 6000 Å most likely due to Na D is not reproduced. The more massive model does a better job of reproducing the observed infrared line shape, but also predicts the unobserved feature near 6100 Å. The early-time spectrum of the low-mass model is far too blue; thus, a more massive model may be slightly favored. Since the predicted infrared feature is produced by a blend of so many elements, and there is no overwhelming evidence for other helium features such as λ5876, it may be premature to conclude that SNe Ic unambiguously contain helium. Thus, we conclude that pure C + O cores are still viable progenitors for SNe Ic.

  8. SN 2010ay Is a Luminous and Broad-Lined Type Ic Supernova Within a Low-Metallicity Host Galaxy

    NASA Technical Reports Server (NTRS)

    Sanders, N. E.; Soderberg, A. M.; Valenti, S.; Foley, R. J.; Chornock, R.; Chomiuk, L.; Berger, E.; Smartt, S.; Hurley, K.; Barthelmy, S. D.; Levesque, E. M.; Narayan, G.; Botticella, M. T.; Briggs, M. S.; Connaughton, V.; Terada, Y.; Gehrels, N.; Golenetskii, S.; Mazets, E.; Cline, T.; von Kienlin, A.; Boynton, W.; Chambers, K. C.; Grav, T.; Heasley, J. N.

    2012-01-01

    We report on our serendipitous pre-discovery detection and follow-up observations of the broad-lined Type Ic supernova (SN Ic) 2010ay at z = 0.067 imaged by the Pan-STARRS1 3pi survey just approximately 4 days after explosion. The supernova (SN) had a peak luminosity, MR approx. -20.2 mag, significantly more luminous than known GRB-SNe and one of the most luminous SNe Ib/c ever discovered. The absorption velocity of SN 2010ay is v Si (is) approx. 19×10(exp 3) km s-1 at approximately 40 days after explosion, 2-5 times higher than other broad-lined SNe and similar to the GRB-SN 2010bh at comparable epochs. Moreover, the velocity declines approximately 2 times slower than other SNe Ic-BL and GRB-SNe. Assuming that the optical emission is powered by radioactive decay, the peak magnitude implies the synthesis of an unusually large mass of 56Ni, MNi = 0.9 solar mass. Applying scaling relations to the light curve, we estimate a total ejecta mass, Mej (is) approx. 4.7 solar mass, and total kinetic energy, EK (is) approx. 11 × 10(exp 51) erg. The ratio of MNi to Mej is approximately 2 times as large for SN 2010ay as typical GRB-SNe and may suggest an additional energy reservoir. The metallicity (log(O/H)PP04 + 12 = 8.19) of the explosion site within the host galaxy places SN 2010ay in the low-metallicity regime populated by GRB-SNe, and (is) approximately 0.5(0.2) dex lower than that typically measured for the host environments of normal (broad-lined) SNe Ic. We constrain any gamma-ray emission with E(gamma) (is) approximately less than 6 × 10(exp 48) erg (25-150 keV), and our deep radio follow-up observations with the Expanded Very Large Array rule out relativistic ejecta with energy E (is) approximately greater than 10(exp 48) erg. We therefore rule out the association of a relativistic outflow like those that accompanied SN 1998bw and traditional long-duration gamma-ray bursts (GRBs), but we place less-stringent constraints on a weak afterglow like that seen from XRF

  9. SN 2010ay is a Luminous and Broad-lined Type Ic Supernova within a Low-metallicity Host Galaxy

    NASA Astrophysics Data System (ADS)

    Sanders, N. E.; Soderberg, A. M.; Valenti, S.; Foley, R. J.; Chornock, R.; Chomiuk, L.; Berger, E.; Smartt, S.; Hurley, K.; Barthelmy, S. D.; Levesque, E. M.; Narayan, G.; Botticella, M. T.; Briggs, M. S.; Connaughton, V.; Terada, Y.; Gehrels, N.; Golenetskii, S.; Mazets, E.; Cline, T.; von Kienlin, A.; Boynton, W.; Chambers, K. C.; Grav, T.; Heasley, J. N.; Hodapp, K. W.; Jedicke, R.; Kaiser, N.; Kirshner, R. P.; Kudritzki, R.-P.; Luppino, G. A.; Lupton, R. H.; Magnier, E. A.; Monet, D. G.; Morgan, J. S.; Onaka, P. M.; Price, P. A.; Stubbs, C. W.; Tonry, J. L.; Wainscoat, R. J.; Waterson, M. F.

    2012-09-01

    We report on our serendipitous pre-discovery detection and follow-up observations of the broad-lined Type Ic supernova (SN Ic) 2010ay at z = 0.067 imaged by the Pan-STARRS1 3π survey just ~4 days after explosion. The supernova (SN) had a peak luminosity, MR ≈ -20.2 mag, significantly more luminous than known GRB-SNe and one of the most luminous SNe Ib/c ever discovered. The absorption velocity of SN 2010ay is v Si ≈ 19 × 103 km s-1 at ~40 days after explosion, 2-5 times higher than other broad-lined SNe and similar to the GRB-SN 2010bh at comparable epochs. Moreover, the velocity declines ~2 times slower than other SNe Ic-BL and GRB-SNe. Assuming that the optical emission is powered by radioactive decay, the peak magnitude implies the synthesis of an unusually large mass of 56Ni, M Ni = 0.9 M ⊙. Applying scaling relations to the light curve, we estimate a total ejecta mass, M ej ≈ 4.7 M ⊙, and total kinetic energy, EK ≈ 11 × 1051 erg. The ratio of M Ni to M ej is ~2 times as large for SN 2010ay as typical GRB-SNe and may suggest an additional energy reservoir. The metallicity (log (O/H)PP04 + 12 = 8.19) of the explosion site within the host galaxy places SN 2010ay in the low-metallicity regime populated by GRB-SNe, and ~0.5(0.2) dex lower than that typically measured for the host environments of normal (broad-lined) SNe Ic. We constrain any gamma-ray emission with E γ <~ 6 × 1048 erg (25-150 keV), and our deep radio follow-up observations with the Expanded Very Large Array rule out relativistic ejecta with energy E >~ 1048 erg. We therefore rule out the association of a relativistic outflow like those that accompanied SN 1998bw and traditional long-duration gamma-ray bursts (GRBs), but we place less-stringent constraints on a weak afterglow like that seen from XRF 060218. If this SN did not harbor a GRB, these observations challenge the importance of progenitor metallicity for the production of relativistic ejecta and suggest that other parameters

  10. SN 2008jb: A 'LOST' CORE-COLLAPSE SUPERNOVA IN A STAR-FORMING DWARF GALAXY AT {approx}10 Mpc

    SciTech Connect

    Prieto, J. L.; Lee, J. C.; Drake, A. J.; Djorgovski, S. G.; McNaught, R.; Garradd, G.; Beacom, J. F.; Beshore, E.; Catelan, M.; Pojmanski, G.; Stanek, K. Z.; Szczygiel, D. M.

    2012-01-20

    We present the discovery and follow-up observations of SN 2008jb, a core-collapse supernova in the southern dwarf irregular galaxy ESO 302-14 (M{sub B} = -15.3 mag) at 9.6 Mpc. This nearby transient was missed by galaxy-targeted surveys and was only found in archival optical images obtained by the Catalina Real-time Transient Survey and the All-Sky Automated Survey. The well-sampled archival photometry shows that SN 2008jb was detected shortly after explosion and reached a bright optical maximum, V{sub max} {approx_equal} 13.6 mag (M{sub V,max} {approx_equal} -16.5). The shape of the light curve shows a plateau of {approx}100 days, followed by a drop of {approx}1.4 mag in the V band to a slow decline with an approximate {sup 56}Co decay slope. The late-time light curve is consistent with 0.04 {+-} 0.01 M{sub Sun} of {sup 56}Ni synthesized in the explosion. A spectrum of the supernova obtained two years after explosion shows a broad, boxy H{alpha} emission line, which is unusual for normal Type II-Plateau supernovae at late times. We detect the supernova in archival Spitzer and WISE images obtained 8-14 months after explosion, which show clear signs of warm (600-700 K) dust emission. The dwarf irregular host galaxy, ESO 302-14, has a low gas-phase oxygen abundance, 12 + log(O/H) = 8.2 ({approx}1/5 Z{sub Sun }), similar to those of the Small Magellanic Cloud and the hosts of long gamma-ray bursts and luminous core-collapse supernovae. This metallicity is one of the lowest among local ({approx}< 10 Mpc) supernova hosts. We study the host environment using GALEX far-UV, R-band, and H{alpha} images and find that the supernova occurred in a large star formation complex. The morphology of the H{alpha} emission appears as a large shell (R {approx_equal} 350 pc) surrounding the FUV and optical emission. Using the H{alpha}-to-FUV ratio and FUV and R-band luminosities, we estimate an age of {approx}9 Myr and a total mass of {approx}2 Multiplication-Sign 10{sup 5} M{sub Sun

  11. Modelling supernova line profile asymmetries to determine ejecta dust masses: SN 1987A from days 714 to 3604

    NASA Astrophysics Data System (ADS)

    Bevan, Antonia; Barlow, M. J.

    2016-02-01

    The late-time optical and near-IR line profiles of many core-collapse supernovae exhibit a red-blue asymmetry as a result of greater extinction by internal dust of radiation emitted from the receding parts of the supernova ejecta. We present here a new code, DAMOCLES, that models the effects of dust on the line profiles of core-collapse supernovae in order to determine newly formed dust masses. We find that late-time dust-affected line profiles may exhibit an extended red scattering wing (as noted by Lucy et al. 1989) and that they need not be flux-biased towards the blue, although the profile peak will always be blueshifted. We have collated optical spectra of SN 1987A from a variety of archival sources and have modelled the Hα line from days 714 to 3604 and the [O I] 6300,6363 Å doublet between days 714 and 1478. Our line profile fits rule out day 714 dust masses >3 × 10-3 M⊙ for all grain types apart from pure magnesium silicates, for which no more than 0.07 M⊙ can be accommodated. Large grain radii ( ≥ 0.6 μm) are generally required to fit the line profiles even at the earlier epochs. We find that a large dust mass (≥0.1 M⊙) had formed by day 3604 and infer that the majority of the present dust mass must have formed after this epoch. Our findings agree with recent estimates from spectral energy distribution fits for the dust mass evolution of SN 1987A and support the inference that the majority of SN 1987A's dust formed many years after the initial explosion.

  12. Optical Observations of the Type Ia Supernova SN 2011fe in M101 for Nearly 500 Days

    NASA Astrophysics Data System (ADS)

    Zhang, Kaicheng; Wang, Xiaofeng; Zhang, JuJia; Zhang, Tianmeng; Ganeshalingam, Mohan; Li, Weidong; Filippenko, Alexei V.; Zhao, Xulin; Zheng, Weikang; Bai, Jinming; Chen, Jia; Chen, Juncheng; Huang, Fang; Mo, Jun; Rui, Liming; Song, Hao; Sai, Hanna; Li, Wenxiong; Wang, Lifan; Wu, Chao

    2016-03-01

    We present well-sampled optical observations of the bright Type Ia supernova (SN Ia) SN 2011fe in M101. Our data, starting from ˜16 days before maximum light and extending to ˜463 days after maximum, provide an unprecedented time series of spectra and photometry for a normal SN Ia. Fitting the early-time rising light curve, we find that the luminosity evolution of SN 2011fe follows a tn law, with the index n being close to 2.0 in the VRI bands but slightly larger in the U and B bands. Combining the published ultraviolet (UV) and near-infrared (NIR) photometry, we derive the contribution of UV/NIR emission relative to the optical. SN 2011fe is found to have stronger UV emission and reaches its UV peak a few days earlier than other SNe Ia with similar Δm15(B), suggestive of less trapping of high-energy photons in the ejecta. Moreover, the U-band light curve shows a notably faster decline at late phases (t ≈ 100-300 days), which also suggests that the ejecta may be relatively transparent to UV photons. These results favor the notion that SN 2011fe might have a progenitor system with relatively lower metallicity. On the other hand, the early-phase spectra exhibit prominent high-velocity features (HVFs) of O i λ7773 and the Ca ii NIR triplet, but only barely detectable in Si ii 6355. This difference can be caused by either an ionization/temperature effect or an abundance enhancement scenario for the formation of HVFs; it suggests that the photospheric temperature of SN 2011fe is intrinsically low, perhaps owing to incomplete burning during the explosion of the white dwarf.

  13. Nearby Supernova Factory II classification of the SN Ia LSQ13yd

    NASA Astrophysics Data System (ADS)

    Feindt, U.; Kowalski, M.; Benitez, S.; Hillebrandt, W.; Kromer, M.; Sasdelli, M.; Sternberg, A.; Taubenberger, S.; Baugh, D.; Chen, J.; Chotard, N.; Wu, C.; Tao, C.; Fouchez, D.; Tilquin, A.; Hadjiyska, E.; Rabinowitz, D.; Baltay, C.; Ellman, N.; McKinnon, R.; Walker, E.; Effron, A.; Cellier-Holzem, F.; Canto, A.; Antilogus, P.; Bongard, S.; Pain, R.; Copin, Y.; Gangler, E.; Pereira, R.; Rigault, M.; Smadja, G.; Aldering, G.; Birchall, D.; Fakhouri, H.; Kim, A.; Nordin, J.; Nugent, P.; Perlmutter, S.; Runge, K.; Saunders, C.; Suzuki, N.; Pecontal, R. C. Thomas E.

    2013-04-01

    The Nearby Supernova Factory II (http://snfactory.lbl.gov) reports the following spectroscopic observations of supernovae based on spectra (range 320-1000 nm) obtained with the SuperNova Integral Field Spectrograph (Aldering et al 2002, SPIE, 4836, 61) on the University of Hawaii 2.2-meter telescope. Classifications were performed using Superfit (Howell et al 2002, BAAS, 34, 1256) or SNID (Blondin & Tonry, 2007, ApJ, 666, 1024).

  14. Type IIb supernova SN 2011dh: Spectra and photometry from the ultraviolet to the near-infrared

    SciTech Connect

    Marion, G. H.; Kirshner, Robert P.; Foley, Ryan J.; Berlind, Perry; Bieryla, Allyson; Calkins, Michael L.; Challis, Peter; Chornock, Ryan; Esquerdo, Gilbert A.; Falco, Emilio E.; Friedman, Andrew S.; Vinko, Jozsef; Bloom, Joshua S.; Chevalier, Roger A.; Culliton, Chris; Curtis, Jason L.; Everett, Mark E.; France, Kevin; Fransson, Claes; Garnavich, Peter; and others

    2014-02-01

    We report spectroscopic and photometric observations of the Type IIb SN 2011dh obtained between 4 and 34 days after the estimated date of explosion (May 31.5 UT). The data cover a wide wavelength range from 2000 Å in the ultraviolet (UV) to 2.4 μm in the near-infrared (NIR). Optical spectra provide line profiles and velocity measurements of H I, He I, Ca II, and Fe II that trace the composition and kinematics of the supernova (SN). NIR spectra show that helium is present in the atmosphere as early as 11 days after the explosion. A UV spectrum obtained with the Space Telescope Imaging Spectrograph reveals that the UV flux for SN 2011dh is low compared to other SN IIb. Modeling the spectrum with SYNOW suggests that the UV deficit is due to line blanketing from Ti II and Co II. The H I and He I velocities in SN 2011dh are separated by about 4000 km s{sup –1} at all phases. A velocity gap is consistent with models for a preexplosion structure in which a hydrogen-rich shell surrounds the progenitor. We estimate that the H shell of SN 2011dh is ≈8 times less massive than the shell of SN 1993J and ≈3 times more massive than the shell of SN 2008ax. Light curves (LCs) for 12 passbands are presented: UVW2, UVM2, UVW1, U, u', B, V, r', i', J, H, and K{sub s} . In the B band, SN 2011dh reached peak brightness of 13.17 mag at 20.0 ± 0.5 after the explosion. The maximum bolometric luminosity of 1.8 ± 0.2 × 10{sup 42} erg s{sup –1} occurred ≈22 days after the explosion. NIR emission provides more than 30% of the total bolometric flux at the beginning of our observations, and the NIR contribution increases to nearly 50% of the total by day 34. The UV produces 16% of the total flux on day 4, 5% on day 9, and 1% on day 34. We compare the bolometric LCs of SN 2011dh, SN 2008ax, and SN 1993J. The LC are very different for the first 12 days after the explosions, but all three SN IIb display similar peak luminosities, times of peak, decline rates, and colors after maximum

  15. Type IIb Supernova SN 2011dh: Spectra and Photometry from the Ultraviolet to the Near-infrared

    NASA Astrophysics Data System (ADS)

    Marion, G. H.; Vinko, Jozsef; Kirshner, Robert P.; Foley, Ryan J.; Berlind, Perry; Bieryla, Allyson; Bloom, Joshua S.; Calkins, Michael L.; Challis, Peter; Chevalier, Roger A.; Chornock, Ryan; Culliton, Chris; Curtis, Jason L.; Esquerdo, Gilbert A.; Everett, Mark E.; Falco, Emilio E.; France, Kevin; Fransson, Claes; Friedman, Andrew S.; Garnavich, Peter; Leibundgut, Bruno; Meyer, Samuel; Smith, Nathan; Soderberg, Alicia M.; Sollerman, Jesper; Starr, Dan L.; Szklenar, Tamas; Takats, Katalin; Wheeler, J. Craig

    2014-02-01

    We report spectroscopic and photometric observations of the Type IIb SN 2011dh obtained between 4 and 34 days after the estimated date of explosion (May 31.5 UT). The data cover a wide wavelength range from 2000 Å in the ultraviolet (UV) to 2.4 μm in the near-infrared (NIR). Optical spectra provide line profiles and velocity measurements of H I, He I, Ca II, and Fe II that trace the composition and kinematics of the supernova (SN). NIR spectra show that helium is present in the atmosphere as early as 11 days after the explosion. A UV spectrum obtained with the Space Telescope Imaging Spectrograph reveals that the UV flux for SN 2011dh is low compared to other SN IIb. Modeling the spectrum with SYNOW suggests that the UV deficit is due to line blanketing from Ti II and Co II. The H I and He I velocities in SN 2011dh are separated by about 4000 km s-1 at all phases. A velocity gap is consistent with models for a preexplosion structure in which a hydrogen-rich shell surrounds the progenitor. We estimate that the H shell of SN 2011dh is ≈8 times less massive than the shell of SN 1993J and ≈3 times more massive than the shell of SN 2008ax. Light curves (LCs) for 12 passbands are presented: UVW2, UVM2, UVW1, U, u', B, V, r', i', J, H, and Ks . In the B band, SN 2011dh reached peak brightness of 13.17 mag at 20.0 ± 0.5 after the explosion. The maximum bolometric luminosity of 1.8 ± 0.2 × 1042 erg s-1 occurred ≈22 days after the explosion. NIR emission provides more than 30% of the total bolometric flux at the beginning of our observations, and the NIR contribution increases to nearly 50% of the total by day 34. The UV produces 16% of the total flux on day 4, 5% on day 9, and 1% on day 34. We compare the bolometric LCs of SN 2011dh, SN 2008ax, and SN 1993J. The LC are very different for the first 12 days after the explosions, but all three SN IIb display similar peak luminosities, times of peak, decline rates, and colors after maximum. This suggests that the

  16. SN 2010ay is a Luminous and Broad-lined Type Ic Supernova within a Low-metallicity Host Galaxy

    NASA Technical Reports Server (NTRS)

    Sanders, N. E.; Soderberg, A. M.; Valenti, S.; Chomiuk, L.; Berger, E.; Smartt, S.; Hurley, K.; Barthelmy, S. D.; Chornock, R.; Foley, R. J.; Levesque, E. M.; Narayan, G.; Botticella, M. T.; Briggs, M. S.; Connaughton, V.; Terada, Y.; Gehrels, N.; Golenetskii, S.; Mazets, E.; Cline, T.; von Kienlin, A.; Boynton, W.; Chambers, K. C.; Grav, T.; Heasley, J. N.

    2011-01-01

    We report on our serendipitous pre-discovery detection and detailed follow-up of the broad-lined Type Ic supernova SN2010ay at z approx 0.067 imaged by the Pan-STARRS1 3pi survey just approx 4 days after explosion. Combining our photometric observations with those available in the literature, we estimate the explosion date and the peak luminosity of the SN, M(sub R) approximately equals 20.2 mag, significantly brighter than known GRB-SNe and one of the most luminous SNe Ibc ever discovered. We measure the photospheric expansion velocity of the explosion from our spectroscopic follow-up observations, v(sub ph) approximately equals 19.2 X 10 (exp 3) km/s at approx 40 days after explosion. In comparison with other broad-lined SNe, the characteristic velocity of SN2010ay is 2 - 5 X higher and similar to the measurements for GRB-SNe at comparable epochs. Moreover the velocity declines two times slower than other SNe Ic-BL and GRB-SNe. Assuming that the optical emission is powered by radioactive decay, the peak magnitude implies the synthesis of an unusually large mass of Ni-56, M(sub Ni) = 0.9(+0.1/-0.1) solar mass. Our modeling of the light-curve points to a total ejecta mass, M(sub ej) approx 4.7 Solar Mass, and total kinetic energy, E(sub K,51) approximately equals 11. Thus the ratio of M(sub Ni) to M(sub ej) is at least twice as large for SN2010ay than in GRB-SNe and may indicate an additional energy reservoir. We also measure the metallicity (log(O/H) + 12 = 8.19) of the explosion site within the host galaxy using a high S/N optical spectrum. Our abundance measurement places this SN in the low-metallicity regime populated by GRB-SNe, and approx 0.2(0.5) dex lower than that typically measured for the host environments of normal (broad-lined) Ic supernovae. Despite striking similarities to the recent GRB-SN100316D/2010bh, we show that gamma-ray observations rule out an associated GRB with E(sub gamma) approx < 6 X 10(exp 48) erg (25-150 keV). Similarly, our deep

  17. Defect energetics and magnetic properties of 3 d-transition-metal-doped topological crystalline insulator SnTe

    NASA Astrophysics Data System (ADS)

    Wang, Na; Wang, JianFeng; Si, Chen; Gu, Bing-Lin; Duan, WenHui

    2016-08-01

    The introduction of magnetism in SnTe-class topological crystalline insulators is a challenging subject with great importance in the quantum device applications. Based on the first-principles calculations, we have studied the defect energetics and magnetic properties of 3 d transition-metal (TM)-doped SnTe. We find that the doped TM atoms prefer to stay in the neutral states and have comparatively high formation energies, suggesting that the uniform TMdoping in SnTe with a higher concentration will be difficult unless clustering. In the dilute doping regime, all the magnetic TMatoms are in the high-spin states, indicating that the spin splitting energy of 3 d TM is stronger than the crystal splitting energy of the SnTe ligand. Importantly, Mn-doped SnTe has relatively low defect formation energy, largest local magnetic moment, and no defect levels in the bulk gap, suggesting that Mn is a promising magnetic dopant to realize the magnetic order for the theoretically-proposed large-Chern-number quantum anomalous Hall effect (QAHE) in SnTe.

  18. ENERGY PARTITION BETWEEN ENERGETIC ELECTRONS AND TURBULENT MAGNETIC FIELD IN SUPERNOVA REMNANT RX J1713.7-3946

    SciTech Connect

    Yang Chuyuan; Liu Siming E-mail: chyy@ynao.ac.cn

    2013-08-20

    Current observations of supernova remnant (SNR) RX J1713.7-3946 favor the leptonic scenario for the TeV emission, where the radio to X-ray emission is produced via the synchrotron process and the {gamma}-ray emission is produced via the inverse Comptonization of soft background photons, and the electron distribution can be inferred from the observed {gamma}-ray spectrum with a spectral inversion method. It is shown that the observed correlation between the X-ray and {gamma}-ray brightness of SNR RX J1713.7-3946 can be readily explained with the assumption that the energy density of energetic electrons is proportional to that of the magnetic field in such a scenario. A two-dimensional magnetohydrodynamic simulation is then carried out to model the overall emission spectrum. It is found that the total energy of electrons above {approx}1 GeV is equal to that of the magnetic field. This is the first piece of observational evidence for energy equipartition between energetic electrons and magnetic field in the downstream of strong collisionless astrophysical shocks of SNRs.

  19. EARLY RADIO AND X-RAY OBSERVATIONS OF THE YOUNGEST NEARBY TYPE Ia SUPERNOVA PTF 11kly (SN 2011fe)

    SciTech Connect

    Horesh, Assaf; Kulkarni, S. R.; Carpenter, John; Kasliwal, Mansi M.; Ofek, Eran O.; Fox, Derek B.; Quimby, Robert; Gal-Yam, Avishay; Cenko, S. Bradley; De Bruyn, A. G.; Kamble, Atish; Wijers, Ralph A. M. J.; Van der Horst, Alexander J.; Kouveliotou, Chryssa; Podsiadlowski, Philipp; Sullivan, Mark; Maguire, Kate; Howell, D. Andrew; Nugent, Peter E.; Gehrels, Neil; and others

    2012-02-10

    On 2011 August 24 (UT) the Palomar Transient Factory (PTF) discovered PTF11kly (SN 2011fe), the youngest and most nearby Type Ia supernova (SN Ia) in decades. We followed this event up in the radio (centimeter and millimeter bands) and X-ray bands, starting about a day after the estimated explosion time. We present our analysis of the radio and X-ray observations, yielding the tightest constraints yet placed on the pre-explosion mass-loss rate from the progenitor system of this supernova. We find a robust limit of M-dot {approx}<10{sup -8}(w/100 km s{sup -1}) M{sub sun} yr{sup -1} from sensitive X-ray non-detections, as well as a similar limit from radio data, which depends, however, on assumptions about microphysical parameters. We discuss our results in the context of single-degenerate models for SNe Ia and find that our observations modestly disfavor symbiotic progenitor models involving a red giant donor, but cannot constrain systems accreting from main-sequence or sub-giant stars, including the popular supersoft channel. In view of the proximity of PTF11kly and the sensitivity of our prompt observations, we would have to wait for a long time (a decade or longer) in order to more meaningfully probe the circumstellar matter of SNe Ia.

  20. Early Radio and X-Ray Observations of the Youngest nearby Type Ia Supernova PTF 11kly (SN 2011fe)

    NASA Astrophysics Data System (ADS)

    Horesh, Assaf; Kulkarni, S. R.; Fox, Derek B.; Carpenter, John; Kasliwal, Mansi M.; Ofek, Eran O.; Quimby, Robert; Gal-Yam, Avishay; Cenko, S. Bradley; de Bruyn, A. G.; Kamble, Atish; Wijers, Ralph A. M. J.; van der Horst, Alexander J.; Kouveliotou, Chryssa; Podsiadlowski, Philipp; Sullivan, Mark; Maguire, Kate; Howell, D. Andrew; Nugent, Peter E.; Gehrels, Neil; Law, Nicholas M.; Poznanski, Dovi; Shara, Michael

    2012-02-01

    On 2011 August 24 (UT) the Palomar Transient Factory (PTF) discovered PTF11kly (SN 2011fe), the youngest and most nearby Type Ia supernova (SN Ia) in decades. We followed this event up in the radio (centimeter and millimeter bands) and X-ray bands, starting about a day after the estimated explosion time. We present our analysis of the radio and X-ray observations, yielding the tightest constraints yet placed on the pre-explosion mass-loss rate from the progenitor system of this supernova. We find a robust limit of \\dot{M}\\lesssim 10^{-8}(w/100\\,km\\,s^{-1})\\,M_{\\odot }\\,yr^{-1} from sensitive X-ray non-detections, as well as a similar limit from radio data, which depends, however, on assumptions about microphysical parameters. We discuss our results in the context of single-degenerate models for SNe Ia and find that our observations modestly disfavor symbiotic progenitor models involving a red giant donor, but cannot constrain systems accreting from main-sequence or sub-giant stars, including the popular supersoft channel. In view of the proximity of PTF11kly and the sensitivity of our prompt observations, we would have to wait for a long time (a decade or longer) in order to more meaningfully probe the circumstellar matter of SNe Ia.

  1. Metamorphosis of SN 2014C: Delayed Interaction between a Hydrogen Poor Core-collapse Supernova and a Nearby Circumstellar Shell

    NASA Astrophysics Data System (ADS)

    Milisavljevic, D.; Margutti, R.; Kamble, A.; Patnaude, D. J.; Raymond, J. C.; Eldridge, J. J.; Fong, W.; Bietenholz, M.; Challis, P.; Chornock, R.; Drout, M. R.; Fransson, C.; Fesen, R. A.; Grindlay, J. E.; Kirshner, R. P.; Lunnan, R.; Mackey, J.; Miller, G. F.; Parrent, J. T.; Sanders, N. E.; Soderberg, A. M.; Zauderer, B. A.

    2015-12-01

    We present optical observations of supernova SN 2014C, which underwent an unprecedented slow metamorphosis from H-poor type Ib to H-rich type IIn over the course of one year. The observed spectroscopic evolution is consistent with the supernova having exploded in a cavity before encountering a massive shell of the progenitor star's stripped hydrogen envelope. Possible origins for the circumstellar shell include a brief Wolf-Rayet fast wind phase that overtook a slower red supergiant wind, eruptive ejection, or confinement of circumstellar material by external influences of neighboring stars. An extended high velocity Hα absorption feature seen in near-maximum light spectra implies that the progenitor star was not completely stripped of hydrogen at the time of core collapse. Archival pre-explosion Subaru Telescope Suprime-Cam and Hubble Space Telescope Wide Field Planetary Camera 2 images of the region obtained in 2009 show a coincident source that is most likely a compact massive star cluster in NGC 7331 that hosted the progenitor system. By comparing the emission properties of the source with stellar population models that incorporate interacting binary stars we estimate the age of the host cluster to be 30-300 Myr, and favor ages closer to 30 Myr in light of relatively strong Hα emission. SN 2014C is the best observed member of a class of core-collapse supernovae that fill the gap between events that interact strongly with dense, nearby environments immediately after explosion and those that never show signs of interaction. Better understanding of the frequency and nature of this intermediate population can contribute valuable information about the poorly understood final stages of stellar evolution.

  2. X-ray emission from the remnant of a carbon deflagration supernova - SN 1572 (Tycho)

    SciTech Connect

    Itoh, H.; Masai, K.; Nomoto, K.

    1988-11-01

    A spherically symmetric hydrodynamic code is used to study the evolution of a young supernova remnant on the basis of a carbon deflagration model for type Ia supernovae. The nonequilibrium X-ray emission has been determined for the elemental composition of the model. The discrepancy between the derived intensity of the Fe D-alpha line blend and the observed value is eliminated by assuming that the stratification of the elemental composition in the supernova ejecta is partially removed by mixing. 59 references.

  3. On the nature of Type IIn/Ia-CSM supernovae: optical and near-infrared spectra of SN 2012ca and SN 2013dn

    NASA Astrophysics Data System (ADS)

    Fox, Ori D.; Silverman, Jeffrey M.; Filippenko, Alexei V.; Mauerhan, Jon; Becker, Juliette; Borish, H. Jacob; Cenko, S. Bradley; Clubb, Kelsey I.; Graham, Melissa; Hsiao, Eric; Kelly, Patrick L.; Lee, William H.; Marion, G. H.; Milisavljevic, Dan; Parrent, Jerod; Shivvers, Isaac; Skrutskie, Michael; Smith, Nathan; Wilson, John; Zheng, Weikang

    2015-02-01

    A growing subset of Type Ia supernovae (SNe Ia) shows evidence via narrow emission lines for unexpected interaction with a dense circumstellar medium (SNe IIn/Ia-CSM). The precise nature of the progenitor, however, remains debated owing to spectral ambiguities arising from a strong contribution from the CSM interaction. Late-time spectra offer potential insight if the post-shock cold, dense shell becomes sufficiently thin and/or the ejecta begin to cross the reverse shock. To date, only a few high-quality spectra of this kind exist. Here we report on the late-time optical and infrared spectra of the SNe Ia-CSM 2012ca and 2013dn. These SNe Ia-CSM spectra exhibit low [Fe III]/[Fe II] ratios and strong [Ca II] at late epochs. Such characteristics are reminiscent of the super-Chandrasekhar-mass candidate SN 2009dc, for which these features suggested a low-ionization state due to high densities, although the broad Fe features admittedly show similarities to the blue `quasi-continuum' observed in some core collapse SNe Ibn and IIn. Neither SN 2012ca nor any of the other SNe Ia-CSM in this paper show evidence for broad oxygen, carbon, or magnesium in their spectra. Similar to the interacting Type IIn SN 2005ip, a number of high-ionization lines are identified in SN 2012ca, including [S III], [Ar III], [Ar X], [Fe VIII], [Fe X], and possibly [Fe XI]. The total bolometric energy output does not exceed 1051 erg, but does require a large kinetic-to-radiative conversion efficiency. All of these observations taken together suggest that SNe Ia-CSM are more consistent with a thermonuclear explosion than a core collapse event, although detailed radiative transfer models are certainly necessary to confirm these results.

  4. Spectroscopy of supernova host galaxies from the SDSS-II SN survey with the SDSS and BOSS spectrographs

    NASA Astrophysics Data System (ADS)

    Olmstead, Matthew Dwaune

    Type Ia supernovae (SNeIa) have been used as standard candles to measure cosmological distances. The initial discovery of the accelerated expansion of the universe was performed using ~50 SNe Ia. Large SNe surveys have increased the number of spectroscopically-confirmed SNe Ia to over a thousand with redshift coverage beyond z = 1. We are now in the age of abundant photometry without the ability for full follow-up spectroscopy of all SN candidates. SN cosmology using these large samples will increasingly rely on robust photometric classification of SN candidates. Photometric classification will increase the sample by including faint SNe as these are preferentially not observed with follow-up spectroscopy. The primary concern with using photometrically classified SNe Ia in cosmology is when a core-collapse SNe is incorrectly classified as an SN Ia. This can be mitigated by obtaining the host galaxy redshift of each SN candidate and using this information as a prior in the photometric classification, removing one degree of freedom. To test the impact of redshift on photometric classification, I have performed an assessment on photometric classification of candidates from the Sloan Digital Sky Survey-II (SDSS-II) SN Survey. I have tested the classification with and without redshift priors by looking at the change of photometric classification, the effect of data quality on photometric classification, and the effect of SN light curve properties on photometric classification. Following our suggested classification scheme, there are a total of 1038 photometrically classified SNe Ia when using a flat redshift prior and 1002 SNe~Ia with the spectroscopic redshift. For 912 (91.0%) candidates classified as likely SNe Ia without redshift information, the classification is unchanged when adding the host galaxy redshift. Finally, I investigate the differences in the interpretation of the light curve properties with and without knowledge of the redshift. When using the SALT2

  5. RADIO EMISSION FROM SN 1994I IN NGC 5194 (M 51): THE BEST-STUDIED TYPE Ib/c RADIO SUPERNOVA

    SciTech Connect

    Weiler, Kurt W.; Panagia, Nino; Stockdale, Christopher; Rupen, Michael; Sramek, Richard A.; Williams, Christopher L. E-mail: panagia@stsci.edu E-mail: mrupen@nrao.edu E-mail: clmw@mit.edu

    2011-10-20

    We present the results of detailed monitoring of the radio emission from the Type Ic supernova SN 1994I from three days after optical discovery on 1994 March 31 until eight years later at age 2927 days on 2002 April 5. The data were mainly obtained using the Very Large Array at the five wavelengths of {lambda}{lambda}1.3, 2.0, 3.6, 6.2, and 21 cm and from the Cambridge 5 km Ryle Telescope at {lambda}2.0 cm. Two additional measurements were obtained at millimeter wavelengths. This data set represents the most complete, multifrequency radio observations ever obtained for a Type Ib/c supernova. The radio emission evolves regularly in both time and frequency and is well described by established supernova emission/absorption models. It is the first radio supernova with sufficient data to show that it is clearly dominated by the effects of synchrotron self-absorption at early times.

  6. SN 2010ay IS A LUMINOUS AND BROAD-LINED TYPE Ic SUPERNOVA WITHIN A LOW-METALLICITY HOST GALAXY

    SciTech Connect

    Sanders, N. E.; Soderberg, A. M.; Foley, R. J.; Chornock, R.; Chomiuk, L.; Berger, E.; Valenti, S.; Smartt, S.; Botticella, M. T.; Hurley, K.; Barthelmy, S. D.; Gehrels, N.; Cline, T.; Levesque, E. M.; Narayan, G.; Briggs, M. S.; Connaughton, V.; Terada, Y.; Golenetskii, S.; Mazets, E.; and others

    2012-09-10

    We report on our serendipitous pre-discovery detection and follow-up observations of the broad-lined Type Ic supernova (SN Ic) 2010ay at z = 0.067 imaged by the Pan-STARRS1 3{pi} survey just {approx}4 days after explosion. The supernova (SN) had a peak luminosity, M{sub R} Almost-Equal-To -20.2 mag, significantly more luminous than known GRB-SNe and one of the most luminous SNe Ib/c ever discovered. The absorption velocity of SN 2010ay is v{sub Si} Almost-Equal-To 19 Multiplication-Sign 10{sup 3} km s{sup -1} at {approx}40 days after explosion, 2-5 times higher than other broad-lined SNe and similar to the GRB-SN 2010bh at comparable epochs. Moreover, the velocity declines {approx}2 times slower than other SNe Ic-BL and GRB-SNe. Assuming that the optical emission is powered by radioactive decay, the peak magnitude implies the synthesis of an unusually large mass of {sup 56}Ni, M{sub Ni} = 0.9 M{sub Sun }. Applying scaling relations to the light curve, we estimate a total ejecta mass, M{sub ej} Almost-Equal-To 4.7 M{sub Sun }, and total kinetic energy, E{sub K} Almost-Equal-To 11 Multiplication-Sign 10{sup 51} erg. The ratio of M{sub Ni} to M{sub ej} is {approx}2 times as large for SN 2010ay as typical GRB-SNe and may suggest an additional energy reservoir. The metallicity (log (O/H){sub PP04} + 12 = 8.19) of the explosion site within the host galaxy places SN 2010ay in the low-metallicity regime populated by GRB-SNe, and {approx}0.5(0.2) dex lower than that typically measured for the host environments of normal (broad-lined) SNe Ic. We constrain any gamma-ray emission with E{sub {gamma}} {approx}< 6 Multiplication-Sign 10{sup 48} erg (25-150 keV), and our deep radio follow-up observations with the Expanded Very Large Array rule out relativistic ejecta with energy E {approx}> 10{sup 48} erg. We therefore rule out the association of a relativistic outflow like those that accompanied SN 1998bw and traditional long-duration gamma-ray bursts (GRBs), but we place less

  7. X-Ray Observations of Type Ia Supernovae with Swift: Evidence of Circumstellar Interaction for SN 2005ke

    NASA Astrophysics Data System (ADS)

    Immler, S.; Brown, P. J.; Milne, P.; The, L.-S.; Petre, R.; Gehrels, N.; Burrows, D. N.; Nousek, J. A.; Williams, C. L.; Pian, E.; Mazzali, P. A.; Nomoto, K.; Chevalier, R. A.; Mangano, V.; Holland, S. T.; Roming, P. W. A.; Greiner, J.; Pooley, D.

    2006-09-01

    We present a study of the early (days to weeks) X-ray and UV properties of eight Type Ia supernovae (SNe Ia) that have been extensively observed with the X-Ray Telescope (XRT) and UV/Optical Telescope (UVOT) on board Swift, ranging from 5 to 132 days after the outburst. SN 2005ke is tentatively detected (at a 3-3.6 σ level of significance) in X-rays based on deep monitoring with the XRT ranging from 8 to 120 days after the outburst. The inferred X-ray luminosity [L0.3-2=(2+/-1)×1038 ergs s-1 0.3-2 keV band] is likely caused by interaction of the SN shock with circumstellar material (CSM) deposited by a stellar wind from the progenitor's companion star with a mass-loss rate of M˙~3×10-6 Msolar yr-1 (vw/10 km s-1). Evidence of CSM interaction in X-rays is independently confirmed by an excess of UV emission, as observed with the UVOT on board Swift, starting around 35 days after the explosion. The nondetection of SN 2005ke with Chandra 105 days after the outburst implies a rate of decline steeper than LX~t-0.75, consistent with the decline expected from the interaction of the SN shock with a spherically symmetric CSM (t-1). None of the other seven SNe Ia is detected in X-rays or shows a UV excess, which allows us to put tight constraints on the mass-loss rates of the progenitor systems.

  8. ACCELERATING VERY FAST GAS IN THE SUPERNOVA IMPOSTOR SN 2009ip WITH JETS FROM A STELLAR COMPANION

    SciTech Connect

    Tsebrenko, Danny; Soker, Noam E-mail: soker@physics.technion.ac.il

    2013-11-10

    Using hydrodynamic numerical simulations we show that high-velocity ejecta with v ∼ 10{sup 4} km s{sup –1} in the outbursts of the supernova impostor SN 2009ip and similar luminous blue variable (LBV) stars can be explained by the interaction of fast jets, having v {sub jet} ∼ 2000-3000 km s{sup –1}, with a circumbinary shell (extended envelope). The density profile in the shell is very steep such that the shock wave, that is excited by the jets' interaction with the shell, accelerates to high velocities as it propagates outward. The amount of very fast ejecta is small, but sufficient to account for some absorption lines. Such an extended envelope can be formed from the binary interaction and/or the unstable phase of the LBV primary star. The jets themselves are launched by the more compact secondary star near periastron passages.

  9. No evidence for an early seventeenth-century Indian sighting of Kepler's supernova (SN1604)

    NASA Astrophysics Data System (ADS)

    van Gent, R. H.

    2013-03-01

    In a recent paper in this journal, Sule et al. (2011) argued that an early 17th-century Indian mural of the constellation Sagittarius with a dragon-headed tail indicated that the bright supernova of 1604 was also sighted by Indian astronomers. In this paper it will be shown that this identification is based on a misunderstanding of traditional Islamic astrological iconography and that the claim that the mural represents an early 17th-century Indian sighting of the supernova of 1604 has to be rejected.

  10. SN 2006oz: rise of a super-luminous supernova observed by the SDSS-II SN Survey

    NASA Astrophysics Data System (ADS)

    Leloudas, G.; Chatzopoulos, E.; Dilday, B.; Gorosabel, J.; Vinko, J.; Gallazzi, A.; Wheeler, J. C.; Bassett, B.; Fischer, J. A.; Frieman, J. A.; Fynbo, J. P. U.; Goobar, A.; Jelínek, M.; Malesani, D.; Nichol, R. C.; Nordin, J.; Östman, L.; Sako, M.; Schneider, D. P.; Smith, M.; Sollerman, J.; Stritzinger, M. D.; Thöne, C. C.; de Ugarte Postigo, A.

    2012-05-01

    Context. A new class of super-luminous transients has recently been identified. These objects reach absolute luminosities of Mu < -21, lack hydrogen in their spectra, and are exclusively discovered by non-targeted surveys because they are associated with very faint galaxies. Aims: We aim to contribute to a better understanding of these objects by studying SN 2006oz, a newly-recognized member of this class. Methods: We present multi-color light curves of SN 2006oz from the SDSS-II SN Survey that cover its rise time, as well as an optical spectrum that shows that the explosion occurred at z ~ 0.376. We fitted black-body functions to estimate the temperature and radius evolution of the photosphere and used the parametrized code SYNOW to model the spectrum. We constructed a bolometric light curve and compared it with explosion models. In addition, we conducted a deep search for the host galaxy with the 10 m GTC telescope. Results: The very early light curves show a dip in the g- and r-bands and a possible initial cooling phase in the u-band before rising to maximum light. The bolometric light curve shows a precursor plateau with a duration of 6-10 days in the rest-frame. A lower limit of Mu < - 21.5 can be placed on the absolute peak luminosity of the SN, while the rise time is constrained to be at least 29 days. During our observations, the emitting sphere doubled its radius to ~2 × 1015 cm, while the temperature remained hot at ~15 000 K. As for other similar SNe, the spectrum is best modeled with elements including O ii and Mg ii, while we tentatively suggest that Fe iii might be present. The host galaxy is detected in gri with 25.74 ± 0.19, 24.43 ± 0.06, and 24.14 ± 0.12, respectively. It is a faint dwarf galaxy with Mg = -16.9. Conclusions: We suggest that the precursor plateau might be related to a recombination wave in a circumstellar medium (CSM) and discuss whether this is a common property of all similar explosions. The subsequent rise can be equally well

  11. Spectropolarimetry of SN 2011dh in M51: geometric insights on a Type IIb supernova progenitor and explosion

    NASA Astrophysics Data System (ADS)

    Mauerhan, Jon C.; Williams, G. Grant; Leonard, Douglas C.; Smith, Paul S.; Filippenko, Alexei V.; Smith, Nathan; Hoffman, Jennifer L.; Huk, Leah; Clubb, Kelsey I.; Silverman, Jeffrey M.; Cenko, S. Bradley; Milne, Peter; Gal-Yam, Avishay; Ben-Ami, Sagi

    2015-11-01

    We present seven epochs of spectropolarimetry of the Type IIb supernova (SN IIb) 2011dh in M51, spanning 86 d of its evolution. The first epoch was obtained 9 d after the explosion, when the photosphere was still in the depleted hydrogen layer of the stripped-envelope progenitor. Continuum polarization is securely detected at the level of P ≈ 0.5 per cent through day 14 and appears to diminish by day 30, which is different from the prevailing trends suggested by studies of other core-collapse SNe. Time-variable modulations in P and position angle are detected across P-Cygni line features. H α and He I polarization peak after 30 d and exhibit position angles roughly aligned with the earlier continuum, while O I and Ca II appear to be geometrically distinct. We discuss several possibilities to explain the evolution of the continuum and line polarization, including the potential effects of a tidally deformed progenitor star, aspherical radioactive heating by fast-rising plumes of 56Ni from the core, oblique shock breakout, or scattering by circumstellar material. While these possibilities are plausible and guided by theoretical expectations, they are not unique solutions to the data. The construction of more detailed hydrodynamic and radiative-transfer models that incorporate complex aspherical geometries will be required to further elucidate the nature of the polarized radiation from SN 2011dh and other SNe IIb.

  12. PUSHing Core-collapse Supernovae to Explosions in Spherical Symmetry I: the Model and the Case of SN 1987A

    NASA Astrophysics Data System (ADS)

    Perego, A.; Hempel, M.; Fröhlich, C.; Ebinger, K.; Eichler, M.; Casanova, J.; Liebendörfer, M.; Thielemann, F.-K.

    2015-06-01

    We report on a method, PUSH, for artificially triggering core-collapse supernova explosions of massive stars in spherical symmetry. We explore basic explosion properties and calibrate PUSH to reproduce SN 1987A observables. Our simulations are based on the GR hydrodynamics code AGILE combined with the neutrino transport scheme isotropic diffusion source approximation for electron neutrinos and advanced spectral leakage for the heavy flavor neutrinos. To trigger explosions in the otherwise non-exploding simulations, the PUSH method increases the energy deposition in the gain region proportionally to the heavy flavor neutrino fluxes. We explore the progenitor range 18-21 {{M}}⊙ . Our studies reveal a distinction between high compactness (HC; compactness parameter {ξ }1.75\\gt 0.45) and low compactness (LC; {ξ }1.75\\lt 0.45) progenitor models, where LC models tend to explode earlier, with a lower explosion energy, and with a lower remnant mass. HC models are needed to obtain explosion energies around 1 Bethe, as observed for SN 1987A. However, all the models with sufficiently high explosion energy overproduce 56Ni and fallback is needed to reproduce the observed nucleosynthesis yields. 57-58Ni yields depend sensitively on the electron fraction and on the location of the mass cut with respect to the shell structure of the progenitor. We identify a progenitor and a suitable set of parameters that fit the explosion properties of SN 1987A assuming 0.1 {{M}}⊙ of fallback. We predict a neutron star with a gravitational mass of 1.50 {{M}}⊙ . We find correlations between explosion properties and the compactness of the progenitor model in the explored mass range. However, a more complete analysis will require exploring of a larger set of progenitors.

  13. Neutrino Signal of Collapse-induced Thermonuclear Supernovae: The Case for Prompt Black Hole Formation in SN 1987A

    NASA Astrophysics Data System (ADS)

    Blum, Kfir; Kushnir, Doron

    2016-09-01

    Collapse-induced thermonuclear explosion (CITE) may explain core-collapse supernovae (CCSNe). We analyze the neutrino signal in CITE and compare it to the neutrino burst of SN 1987A. For strong (≳ {10}51 erg) CCSNe, such as SN 1987A, CITE predicts a proto-neutron star (PNS) accretion phase lasting up to a few seconds that is cut off by black hole (BH) formation. The neutrino luminosity can later be revived by accretion disk emission after a dead time of a few to a few tens of seconds. In contrast, the neutrino mechanism for CCSNe predicts a short (≲s) PNS accretion phase, followed by slowly declining PNS cooling luminosity. We repeat statistical analyses used in the literature to interpret the neutrino mechanism, and apply them to CITE. The first 1–2 s of the neutrino burst are equally compatible with CITE and with the neutrino mechanism. However, the data points toward a luminosity drop at t = 2–3 s, which is in some tension with the neutrino mechanism but can be naturally attributed to BH formation in CITE. The occurrence of neutrino signal events at 5 s suggests that, within CITE, the accretion disk formed by that time. We perform two-dimensional numerical simulations showing that CITE may be able to accommodate this disk formation time while reproducing the ejected 56Ni mass and ejecta kinetic energy within factors of 2–3 of observations. We estimate the accretion disk neutrino luminosity, finding it to be on the low side but compatible with the data to a factor of 10. Given comparable uncertainties in the disk luminosity simulation, we conclude that direct BH formation may have occurred in SN 1987A.

  14. Nebular spectra and abundance tomography of the Type Ia supernova SN 2011fe: a normal SN Ia with a stable Fe core

    NASA Astrophysics Data System (ADS)

    Mazzali, P. A.; Sullivan, M.; Filippenko, A. V.; Garnavich, P. M.; Clubb, K. I.; Maguire, K.; Pan, Y.-C.; Shappee, B.; Silverman, J. M.; Benetti, S.; Hachinger, S.; Nomoto, K.; Pian, E.

    2015-07-01

    A series of optical and one near-infrared nebular spectra covering the first year of the Type Ia supernova SN 2011fe are presented and modelled. The density profile that proved best for the early optical/ultraviolet spectra, `ρ-11fe', was extended to lower velocities to include the regions that emit at nebular epochs. Model ρ-11fe is intermediate between the fast deflagration model W7 and a low-energy delayed-detonation. Good fits to the nebular spectra are obtained if the innermost ejecta are dominated by neutron-rich, stable Fe-group species, which contribute to cooling but not to heating. The correct thermal balance can thus be reached for the strongest [Fe II] and [Fe III] lines to be reproduced with the observed ratio. The 56Ni mass thus obtained is ˜0.47 ± 0.05 M⊙. The bulk of 56Ni has an outermost velocity of ˜8500 km s-1. The mass of stable iron is ˜0.23 ± 0.03 M⊙. Stable Ni has low abundance, ˜10-2 M⊙. This is sufficient to reproduce an observed emission line near 7400 Å. A sub-Chandrasekhar explosion model with mass 1.02 M⊙ and no central stable Fe does not reproduce the observed line ratios. A mock model where neutron-rich Fe-group species are located above 56Ni following recent suggestions is also shown to yield spectra that are less compatible with the observations. The densities and abundances in the inner layers obtained from the nebular analysis, combined with those of the outer layers previously obtained, are used to compute a synthetic bolometric light curve, which compares favourably with the light curve of SN 2011fe.

  15. SALT spectroscopic classification of ASASSN-16cc (SN 2016aqf) as a type-II supernova

    NASA Astrophysics Data System (ADS)

    Jha, S. W.; Miszalski, B.

    2016-02-01

    We obtained SALT (+RSS) spectroscopy of ASASSN-16cc (SN 2016aqf) on 2016 February 27.9 UT, covering the wavelength range 360-920 nm. The spectrum features a blue continuum with prominent P-Cygni lines of H and He. Cross-correlation of the spectrum with a template library using SNID (Blondin & Tonry 2007, ApJ, 666, 1024) shows a good match to the type-IIP SN 2014et at -3 days, confirming the results of Hosseinzadeh et al. (ATel 8748).

  16. Applying the expanding photosphere and standardized candle methods to Type II-Plateau supernovae at cosmologically significant redshifts . The distance to SN 2013eq

    NASA Astrophysics Data System (ADS)

    Gall, E. E. E.; Kotak, R.; Leibundgut, B.; Taubenberger, S.; Hillebrandt, W.; Kromer, M.

    2016-08-01

    Based on optical imaging and spectroscopy of the Type II-Plateau SN 2013eq, we present a comparative study of commonly used distance determination methods based on Type II supernovae. The occurrence of SN 2013eq in the Hubble flow (z = 0.041 ± 0.001) prompted us to investigate the implications of the difference between "angular" and "luminosity" distances within the framework of the expanding photosphere method (EPM) that relies upon a relation between flux and angular size to yield a distance. Following a re-derivation of the basic equations of the EPM for SNe at non-negligible redshifts, we conclude that the EPM results in an angular distance. The observed flux should be converted into the SN rest frame and the angular size, θ, has to be corrected by a factor of (1 + z)2. Alternatively, the EPM angular distance can be converted to a luminosity distance by implementing a modification of the angular size. For SN 2013eq, we find EPM luminosity distances of DL = 151 ± 18 Mpc and DL = 164 ± 20 Mpc by making use of different sets of dilution factors taken from the literature. Application of the standardized candle method for Type II-P SNe results in an independent luminosity distance estimate (DL = 168 ± 16 Mpc) that is consistent with the EPM estimate. Spectra of SN 2013eq are available in the Weizmann Interactive Supernova data REPository (WISeREP): http://wiserep.weizmann.ac.il

  17. Spectroscopic Classification of SN 2016aqt as an Overluminous Type Ia Supernova

    NASA Astrophysics Data System (ADS)

    Rui, L.; Hosseinzadeh, G.; Yang, Y.; Arcavi, I.; Howell, D. A.; McCully, C.; Valenti, S.; Wang, X.; Huang, F.; Zhai, M.; Zhang, T.; Wang, L.

    2016-03-01

    We obtained two optical spectra of SN 2016aqt, discovered by R. Gagliano, J. Newton, R. Post, and T. Puckett (POSS), on 2016 March 2.7 UT with the Xinglong 2.16-m telescope (China) and on 2016 March 4.7 UT with the robotic FLOYDS instrument mounted on the LCOGT 2-meter telescope in Siding Spring (Australia).

  18. Spectroscopic Classification of SN 2016ccs as a Type Ia Supernova

    NASA Astrophysics Data System (ADS)

    Zhang, J.-J.; Wang, C.-J.; Xu, Z.; Li, W.; Yang, Z.; Wang, X.-F.; Zhang, T.-M.

    2016-05-01

    We obtained an optical spectrum (range 340-900 nm) of SN 2016ccs (AT2016ccs), discovered by the Tsinghua-NAOC Transient Survey (TNTS), on UT May 11.71 2016 with the 2.4 m telescope (LJT + YFOSC) at LiJiang Observatory of Yunnan Observatories (YNAO).

  19. Spectroscopic Classification of SN 2016bsc as a Type Ia Supernova

    NASA Astrophysics Data System (ADS)

    Zhang, Jujia; Wang, Jianguo; Zhang, Tianmeng; Li, Wenxiong; Wang, Xiaofeng

    2016-05-01

    We obtained an optical spectrum (range 340-900 nm) of SN 2016bsc (AT2016bsc), discovered by the Tsinghua-NAOC Transient Survey (TNTS), on UT May 01.58 2016 with the 2.4 m telescope (LJT + YFOSC) at LiJiang Observatory of Yunnan Observatories (YNAO).

  20. Spectroscopic Classification of SN 2016cor as a Type Ia Supernova

    NASA Astrophysics Data System (ADS)

    Zhang, Jujia; Zhang, Tianmeng; Li, Wenxiong; Wang, Xiaofeng

    2016-05-01

    We obtained an optical spectrum (range 380-870 nm) of SN 2016cor (AT2016cor), discovered by the Tsinghua-NAOC Transient Survey (TNTS), on UT May 31.68 2016 with the 2.4 m telescope (LJT + YFOSC) at Lijiang Observatory of Yunnan Observatories (YNAO).

  1. Spectroscopic Classification of SN 2016aqv as a Type IIn Supernova

    NASA Astrophysics Data System (ADS)

    Zhang, Jujia; Wang, Chuanjun; Wang, Xiaofeng; Li, Wenxiong; Yang, Zesheng; Li, Bin; Zhao, Haibin; Wang, Lifan

    2016-03-01

    We report an optical spectrum (range 340-900 nm) of SN 2016aqv (ATEL #8757) that was obtained on UT Mar.01.8 2016 with the 2.4-m telescope (+YFOSC) at LiJiang Gaomeigu Station of Yunnan Astronomical Observatories (YNAO).

  2. Spectroscopic Classification of SN 2016aqz as a Type Ia Supernova

    NASA Astrophysics Data System (ADS)

    Rui, Liming; Wang, Xiaofeng; Huang, Fang; Zhai, Meng; Zhang, Tianmeng

    2016-03-01

    We report an optical spectrum (range 380-850 nm) of SN 2016aqz (ATEL #8763) that was obtained on UT Mar.02.69 2016 with the 2.16-m telescope (+BFOSC) at the Xinglong Station of National Astronomical Observatories of China (NAOC).

  3. SALT spectroscopic classification of LSQ16acz (= PS16bby = SN 2016bew) as a type-Ia supernova approaching maximum light

    NASA Astrophysics Data System (ADS)

    Jha, S. W.; Pan, Y.-C.; Foley, R. J.; Rest, A.; Scolnic, D.; Kotze, M.

    2016-03-01

    We obtained SALT (+RSS) spectroscopy of LSQ16acz (= PS16bby = SN 2016bew; Baltay et al. 2013, PASP, 125, 683) on 2016 Mar 14.9 UT, covering the wavelength range 340-920 nm. Cross-correlation of the spectrum with a template library using SNID (Blondin & Tonry 2007, ApJ, 666, 1024) shows LSQ16acz is a type-Ia supernova a few days before maximum light.

  4. The Radio and X-Ray Luminous SN 2003bg and the Circumstellar Density Variations around Radio Supernovae

    NASA Astrophysics Data System (ADS)

    Soderberg, A. M.; Chevalier, R. A.; Kulkarni, S. R.; Frail, D. A.

    2006-11-01

    We report extensive radio and X-ray observations of SN 2003bg, whose spectroscopic evolution shows a transition from a broad-lined Type Ic to a hydrogen-rich Type II, and later to a typical hydrogen-poor Type Ibc. We show that the extraordinarily luminous radio emission is well described by a self-absorption-dominated synchrotron spectrum, while the observed X-ray emission at t~30 days is adequately fit by inverse Compton scattering of the optical photons off of the synchrotron-emitting electrons. Our radio model implies a subrelativistic ejecta velocity, v~0.24c, at t0~10 days after the explosion, which emphasizes that broad optical absorption lines do not imply relativistic ejecta. We find that the total energy of the radio-emitting region evolves as E~7.3×1048(t/t0)0.4 ergs, assuming equipartition of energy between relativistic electrons and magnetic fields (ɛe=ɛB=0.1). The circumstellar density is well described by a stellar wind profile, with modest (factor of ~2) episodic density enhancements that produce abrupt achromatic flux variations. We estimate an average mass-loss rate of M˙~3×10-4 Msolar yr-1 (assuming a wind velocity of vw=103 km s-1) for the progenitor, consistent with the observed values for Galactic Wolf-Rayet stars. Comparison with other events reveals that ~50% of radio supernovae show similar short-timescale flux variations, attributable to circumstellar density irregularities. Specifically, the radio light curves of SN 2003bg are strikingly similar to those of the Type IIb SN 2001ig, suggestive of a common progenitor evolution for these two events. Based on the relative intensity of the inferred density enhancements, we conclude that the progenitors of SNe 2003bg and 2001ig experienced quasi-periodic mass-loss episodes just prior to the SN explosion. Finally, this study emphasizes that abrupt radio light-curve variations cannot be used as a reliable proxy for an engine-driven explosion, including off-axis gamma-ray bursts.

  5. H II Region Metallicity Constraints Near the Site of the Strongly Lensed SupernovaSN Refsdal” at Redshift 1.49

    NASA Astrophysics Data System (ADS)

    Yuan, Tiantian; Kobayashi, Chiaki; Kewley, Lisa J.

    2015-05-01

    We present the local H ii region metallicity near the site of the recently discovered multiply lensed supernova (SN; “SN Refsdal”) at redshift 1.49. “SN Refsdal” is located at the outer spiral arm (˜7 kpc) of the lensed host galaxy, which we previously reported to exhibit a steep negative galactocentric metallicity gradient. Based on our updated near-infrared integral field spectroscopic data, the gas-phase metallicity averaged in an intrinsic radius of ˜550 pc surrounding an H ii region ˜200 pc away from the SN site is 12 + log(O/H)PP04N2≤slant 8.67. The metallicity averaged over nine H ii regions at similar galactocentric distances (˜5-7 kpc) as “SN Refsdal” is constrained to be 12 + log(O/H)PP04N2≤slant 8.11. Given the fortuitous discovery of “SN Refsdal” in an advantageously lensed face-on spiral, this is the first observational constraint on the local metallicity environment of an SN site at redshift z\\gt 1.

  6. DISCOVERY AND EARLY MULTI-WAVELENGTH MEASUREMENTS OF THE ENERGETIC TYPE IC SUPERNOVA PTF12GZK: A MASSIVE-STAR EXPLOSION IN A DWARF HOST GALAXY

    SciTech Connect

    Ben-Ami, Sagi; Gal-Yam, Avishay; Yaron, Ofer; Arcavi, Iair; Filippenko, Alexei V.; Cenko, S. Bradley; Mazzali, Paolo A.; Modjaz, Maryam; Horesh, Assaf; Kulkarni, Shrinivas R.; Perley, Daniel; Howell, D. Andrew; Graham, Melissa L.; Sand, David J.; Horst, J. Chuck; Leonard, Douglas C.; Im, Myunshin; Jeon, Yiseul; Sullivan, Mark; and others

    2012-12-01

    We present the discovery and extensive early-time observations of the Type Ic supernova (SN) PTF12gzk. Our light curves show a rise of 0.8 mag within 2.5 hr. Power-law fits (f(t){proportional_to}(t - t{sub 0}) {sup n}) to these data constrain the explosion date to within one day. We cannot rule out a quadratic fireball model, but higher values of n are possible as well for larger areas in the fit parameter space. Our bolometric light curve and a dense spectral sequence are used to estimate the physical parameters of the exploding star and of the explosion. We show that the photometric evolution of PTF12gzk is slower than that of most SNe Ic. The high ejecta expansion velocities we measure ({approx}30, 000 km s{sup -1} derived from line minima four days after explosion) are similar to the observed velocities of broad-lined SNe Ic associated with gamma-ray bursts (GRBs) rather than to normal SN Ic velocities. Yet, this SN does not show the persistent broad lines that are typical of broad-lined SNe Ic. The host-galaxy characteristics are also consistent with GRB-SN hosts, and not with normal SN Ic hosts. By comparison with the spectroscopically similar SN 2004aw, we suggest that the observed properties of PTF12gzk indicate an initial progenitor mass of 25-35 M{sub Sun} and a large ((5-10) Multiplication-Sign 10{sup 51} erg) kinetic energy, the later being close to the regime of GRB-SN properties.

  7. Origin of pulsed emission from the young supernova remnant SN 1987A

    NASA Technical Reports Server (NTRS)

    Ruderman, M.; Kluzniak, W.; Shaham, Jacob

    1989-01-01

    To overcome difficulties in understanding the origin of the submillisecond optical pulses from SN 1987A a model similar to that of Kundt and Krotscheck for pulsed synchrotron emission from the Crab was applied. The interaction of the expected ultrarelativistic e(sup + or -) pulsar wind with the pulsar dipole electromagnetic wave reflected from the walls of a pulsar cavity within the SN 1987A nubula can generate pulsed optical emission with efficiency at most eta(sub max) is approximately equal to 10(exp -3). The maximum luminosity of the source is reproduced and other observational constraints can be satisfied for an average wind energy flow is approximately equal to 10(exp 38) erg/(s steradian) and for electron Lorentz factor gamma is approximately equal to 10(exp 5). This model applied to the Crab yields pulsations of much lower luminosity and frequency.

  8. A model of the pre-Sedov expansion phase of supernova remnant-ambient plasma coupling and X-ray emission from SN 1987A

    NASA Technical Reports Server (NTRS)

    Spicer, D. S.; Maran, S. P.; Clark, R. W.

    1990-01-01

    This paper examines the mechanism responsible for coupling supernova (SN) remnant to the ambient medium during the pre-Sedov or the so-called free expansion phase, immediately following the progenitor explosion. A theory is developed for the interaction of an SN piston with the ambient medium during the pre-Sedov phase. The possibility of X-ray production by the high-speed portion of the piston during this phase is investigated. The relevant observations of high-energy emissions from the SN 1987A, including the X-ray spectrum, luminosity, and temporal development, are considered. It is shown that the commonly assumed snowplow model for SNR evolution is valid, because of the action of a variety of collisionless two-stream instabilities that permit the coupling of the ambient plasma with SNR.

  9. OISTER optical and near-infrared observations of the super-Chandrasekhar supernova candidate SN 2012dn: Dust emission from the circumstellar shell

    NASA Astrophysics Data System (ADS)

    Yamanaka, Masayuki; Maeda, Keiichi; Tanaka, Masaomi; Tominaga, Nozomu; Kawabata, Koji S.; Takaki, Katsutoshi; Kawabata, Miho; Nakaoka, Tatsuya; Ueno, Issei; Akitaya, Hiroshi; Nagayama, Takahiro; Takahashi, Jun; Honda, Satoshi; Omodaka, Toshihiro; Miyanoshita, Ryo; Nagao, Takashi; Watanabe, Makoto; Isogai, Mizuki; Arai, Akira; Itoh, Ryosuke; Ui, Takahiro; Uemura, Makoto; Yoshida, Michitoshi; Hanayama, Hidekazu; Kuroda, Daisuke; Ukita, Nobuharu; Yanagisawa, Kenshi; Izumiura, Hideyuki; Saito, Yoshihiko; Masumoto, Kazunari; Ono, Rikako; Noguchi, Ryo; Matsumoto, Katsura; Nogami, Daisaku; Morokuma, Tomoki; Oasa, Yumiko; Sekiguchi, Kazuhiro

    2016-05-01

    We present extensively dense observations of the super-Chandrasekhar supernova (SC SN) candidate SN 2012dn from -11 to +140 d after the date of its B-band maximum in the optical and near-infrared (NIR) wavelengths conducted through the OISTER ToO (Optical and Infrared Synergetic Telescopes for Education and Research Target of Opportunity) program. The NIR light curves and color evolutions up to 35 days after the B-band maximum provided an excellent match with those of another SC SN 2009dc, providing further support to the nature of SN 2012dn as an SC SN. We found that SN 2012dn exhibited strong excesses in the NIR wavelengths from 30 d after the B-band maximum. The H- and Ks-band light curves exhibited much later maximum dates at 40 and 70 d after the B-band maximum, respectively, compared with those of normal SNe Ia. The H- and Ks-band light curves subtracted by those of SN 2009dc displayed plateaued evolutions, indicating an NIR echo from the surrounding dust. The distance to the inner boundary of the dust shell is limited to 4.8-6.4 × 10-2 pc. No emission lines were found in its early phase spectra, suggesting that the ejecta-circumstellar material interaction could not occur. On the other hand, we found no signature that strongly supports the scenario of dust formation. The mass-loss rate of the pre-explosion system is estimated to be 10-6-10-5 M⊙ yr-1, assuming that the wind velocity of the system is 10-100 km s-1, which suggests that the progenitor of SN 2012dn could be a recurrent nova system. We conclude that the progenitor of this SC SN could be explained by the single-degenerate scenario.

  10. Aspherical supernovae

    SciTech Connect

    Kasen, Daniel Nathan

    2004-05-21

    Although we know that many supernovae are aspherical, the exact nature of their geometry is undetermined. Because all the supernovae we observe are too distant to be resolved, the ejecta structure can't be directly imaged, and asymmetry must be inferred from signatures in the spectral features and polarization of the supernova light. The empirical interpretation of this data, however, is rather limited--to learn more about the detailed supernova geometry, theoretical modeling must been undertaken. One expects the geometry to be closely tied to the explosion mechanism and the progenitor star system, both of which are still under debate. Studying the 3-dimensional structure of supernovae should therefore provide new break throughs in our understanding. The goal of this thesis is to advance new techniques for calculating radiative transfer in 3-dimensional expanding atmospheres, and use them to study the flux and polarization signatures of aspherical supernovae. We develop a 3-D Monte Carlo transfer code and use it to directly fit recent spectropolarimetric observations, as well as calculate the observable properties of detailed multi-dimensional hydrodynamical explosion simulations. While previous theoretical efforts have been restricted to ellipsoidal models, we study several more complicated configurations that are tied to specific physical scenarios. We explore clumpy and toroidal geometries in fitting the spectropolarimetry of the Type Ia supernova SN 2001el. We then calculate the observable consequences of a supernova that has been rendered asymmetric by crashing into a nearby companion star. Finally, we fit the spectrum of a peculiar and extraordinarily luminous Type Ic supernova. The results are brought to bear on three broader astrophysical questions: (1) What are the progenitors and the explosion processes of Type Ia supernovae? (2) What effect does asymmetry have on the observational diversity of Type Ia supernovae, and hence their use in cosmology? (3) And

  11. Aspherical supernovae

    NASA Astrophysics Data System (ADS)

    Kasen, Daniel Nathan

    Although we know that many supernovae are aspherical, the exact nature of their geometry is undetermined. Because all the supernovae we observe are too distant to be resolved, the ejecta structure can't be directly imaged, and asymmetry must be inferred from signatures in the spectral features and polarization of the supernova light. The empirical interpretation of this data, however, is rather limited--to learn more about the detailed supernova geometry, theoretical modeling must be undertaken. One expects the geometry to be closely tied to the explosion mechanism and the progenitor star system, both of which are still under debate. Studying the 3-dimensional structure of supernovae should therefore provide new breakthroughs in our understanding. The goal of this thesis is to advance new techniques for calculating radiative transfer in 3-dimensional expanding atmospheres, and use them to study the flux and polarization signatures of aspherical supernovae. We develop a 3-D Monte Carlo transfer code and use it to directly fit recent spectropolarimetric observations, as well as calculate the observable properties of detailed multi- dimensional hydrodynamical explosion simulations. While previous theoretical efforts have been restricted to ellipsoidal models, we study several more complicated configurations that are tied to specific physical scenarios. We explore clumpy and toroidal geometries in fitting the spectropolarimetry of the Type Ia supernova SN 2001el. We then calculate the observable consequences of a supernova that has been rendered asymmetric by crashing into a nearby companion star. Finally we fit the spectrum of a peculiar and extraordinarily luminous Type Ic supernova. The results are brought to bear on three broader astrophysical questions: (1) What are the progenitors and the explosion processes of Type Ia supernovae? (2) What effect does asymmetry have on the observational diversity of Type Ia supernovae, and hence their use in cosmology? (3) And

  12. Particle acceleration and production of energetic photons in SN1987A

    NASA Technical Reports Server (NTRS)

    Gaisser, T. K.; Stanev, Todor; Harding, Alice

    1987-01-01

    A pulsar wind model for the acceleration of particles in SN1987A is discussed. The expected photon flux is investigated in terms of the spectrum of parent protons and electrons, the nature of the region in which they propagate after acceleration, and the magnetic field and radiation environment which determines the subsequent fate of produced photons. The model is found to produce observable signals if the spin period of the pulsar is 10 ms or less.

  13. The broad-lined Type Ic supernova 2003jd

    NASA Astrophysics Data System (ADS)

    Valenti, S.; Benetti, S.; Cappellaro, E.; Patat, F.; Mazzali, P.; Turatto, M.; Hurley, K.; Maeda, K.; Gal-Yam, A.; Foley, R. J.; Filippenko, A. V.; Pastorello, A.; Challis, P.; Frontera, F.; Harutyunyan, A.; Iye, M.; Kawabata, K.; Kirshner, R. P.; Li, W.; Lipkin, Y. M.; Matheson, T.; Nomoto, K.; Ofek, E. O.; Ohyama, Y.; Pian, E.; Poznanski, D.; Salvo, M.; Sauer, D. N.; Schmidt, B. P.; Soderberg, A.; Zampieri, L.

    2008-02-01

    The results of a worldwide coordinated observational campaign on the broad-lined Type Ic supernova (SN Ic) 2003jd are presented. In total, 74 photometric data points and 26 spectra were collected using 11 different telescopes. SN 2003jd is one of the most luminous SN Ic ever observed. A comparison with other Type Ic supernovae (SNe Ic) confirms that SN 2003jd represents an intermediate case between broad-line events (2002ap, 2006aj) and highly energetic SNe (1997ef, 1998bw, 2003dh, 2003lw), with an ejected mass of Mej = 3.0 +/- 1Msolar and a kinetic energy of Ek(tot) = 7+3-2 × 1051erg. SN 2003jd is similar to SN 1998bw in terms of overall luminosity, but it is closer to SNe 2006aj and 2002ap in terms of light-curve shape and spectral evolution. The comparison with other SNe Ic suggests that the V-band light curves of SNe Ic can be partially homogenized by introducing a time-stretch factor. Finally, because of the similarity of SN 2003jd to the SN 2006aj/XRF 060218 event, we discuss the possible connection of SN 2003jd with a gamma-ray burst (GRB). E-mail: svalenti@eso.org Based on observations at ESO-Paranal, Prog. 074.D-0161A.

  14. Radio Observations of SN 2008ha

    NASA Astrophysics Data System (ADS)

    Soderberg, Alicia

    2009-03-01

    I observed the peculiar SN 2008ha (CBET #1567) with the Very Large Array on 2008 Nov 21.99 UT at a frequency of 8.46 GHz. No radio source is detected at the optical SN position to a limit of 93 microJy (3 sigma). At a distance of 21 Mpc, this corresponds to a radio luminosity limit similar to those of nearby Type Ia supernovae (Panagia et al. 2006). It is also consistent with the observed radio luminosities for the nearest Type Ibc supernovae (e.g., SN 2002ap; Berger, Kulkarni & Chevalier 2002), but a factor of 10^3 and 10^5 below the radio luminosities of sub-energetic GRBs (Soderberg et al.

  15. Spectroscopic Observations of SN 2012fr: A Luminous, Normal Type Ia Supernova with Early High-velocity Features and a Late Velocity Plateau

    NASA Astrophysics Data System (ADS)

    Childress, M. J.; Scalzo, R. A.; Sim, S. A.; Tucker, B. E.; Yuan, F.; Schmidt, B. P.; Cenko, S. B.; Silverman, J. M.; Contreras, C.; Hsiao, E. Y.; Phillips, M.; Morrell, N.; Jha, S. W.; McCully, C.; Filippenko, A. V.; Anderson, J. P.; Benetti, S.; Bufano, F.; de Jaeger, T.; Forster, F.; Gal-Yam, A.; Le Guillou, L.; Maguire, K.; Maund, J.; Mazzali, P. A.; Pignata, G.; Smartt, S.; Spyromilio, J.; Sullivan, M.; Taddia, F.; Valenti, S.; Bayliss, D. D. R.; Bessell, M.; Blanc, G. A.; Carson, D. J.; Clubb, K. I.; de Burgh-Day, C.; Desjardins, T. D.; Fang, J. J.; Fox, O. D.; Gates, E. L.; Ho, I.-T.; Keller, S.; Kelly, P. L.; Lidman, C.; Loaring, N. S.; Mould, J. R.; Owers, M.; Ozbilgen, S.; Pei, L.; Pickering, T.; Pracy, M. B.; Rich, J. A.; Schaefer, B. E.; Scott, N.; Stritzinger, M.; Vogt, F. P. A.; Zhou, G.

    2013-06-01

    We present 65 optical spectra of the Type Ia SN 2012fr, 33 of which were obtained before maximum light. At early times, SN 2012fr shows clear evidence of a high-velocity feature (HVF) in the Si II λ6355 line that can be cleanly decoupled from the lower velocity "photospheric" component. This Si II λ6355 HVF fades by phase -5 subsequently, the photospheric component exhibits a very narrow velocity width and remains at a nearly constant velocity of ~12,000 km s-1 until at least five weeks after maximum brightness. The Ca II infrared triplet exhibits similar evidence for both a photospheric component at v ≈ 12,000 km s-1 with narrow line width and long velocity plateau, as well as an HVF beginning at v ≈ 31,000 km s-1 two weeks before maximum. SN 2012fr resides on the border between the "shallow silicon" and "core-normal" subclasses in the Branch et al. classification scheme, and on the border between normal and high-velocity Type Ia supernovae (SNe Ia) in the Wang et al. system. Though it is a clear member of the "low velocity gradient" group of SNe Ia and exhibits a very slow light-curve decline, it shows key dissimilarities with the overluminous SN 1991T or SN 1999aa subclasses of SNe Ia. SN 2012fr represents a well-observed SN Ia at the luminous end of the normal SN Ia distribution and a key transitional event between nominal spectroscopic subclasses of SNe Ia.

  16. Analysis of the flux and polarization spectra of the type Ia supernova SN 2001el: Exploring the geometry of the high-velocity Ejecta

    SciTech Connect

    Kasen, Daniel; Nugent, Peter; Wang, Lifan; Howell, D.A.; Wheeler, J. Craig; Hoeflich, Peter; Baade, Dietrich; Baron, E.; Hauschildt, P.H.

    2003-01-15

    SN 2001el is the first normal Type Ia supernova to show a strong, intrinsic polarization signal. In addition, during the epochs prior to maximum light, the CaII IR triplet absorption is seen distinctly and separately at both normal photospheric velocities and at very high velocities. The unusual, high-velocity triplet absorption is highly polarized, with a different polarization angle than the rest of the spectrum. The unique observation allows us to construct a relatively detailed picture of the layered geometrical structure of the supernova ejecta: in our interpretation, the ejecta layers near the photosphere (v approximately 10,000 km/s) obey a near axial symmetry, while a detached, high-velocity structure (v approximately 18,000-25,000 $ km/s) of CaII line opacity deviates from the photospheric axisymmetry. By partially obscuring the underlying photosphere, the high-velocity structure causes a more incomplete cancellation of the polarization of the photospheric light, and so gives rise to the polarization peak of the high-velocity IR triplet feature. In an effort to constrain the ejecta geometry, we develop a technique for calculating 3-D synthetic polarization spectra and use it to generate polarization profiles for several parameterized configurations. In particular, we examine the case where the inner ejecta layers are ellipsoidal and the outer, high-velocity structure is one of four possibilities: a spherical shell, an ellipsoidal shell, a clumped shell, or a toroid. The synthetic spectra rule out the clearly discriminated if observations are obtained from several different lines of sight. Thus, assuming the high velocity structure observed for SN 2001el is a consistent feature of at least known subset of type Ia supernovae, future observations and analyses such as these may allow one to put strong constraints on the ejecta geometry and hence on supernova progenitors and explosion mechanisms.

  17. Nearby Supernova Factory II classification of the SN Ia LSQ13ads and non-detection of LSQ13acp

    NASA Astrophysics Data System (ADS)

    Baugh, D.; Chen, J.; Chotard, N.; Wu, C.; Tao, C.; Fouchez, D.; Tilquin, A.; Hadjiyska, E.; Rabinowitz, D.; Baltay, C.; Ellman, N.; McKinnon, R.; Walker, E.; Effron, A.; Cellier-Holzem, F.; Canto, A.; Antilogus, P.; Bongard, S.; Pain, R.; Copin, Y.; Gangler, E.; Pereira, R.; Rigault, M.; Smadja, G.; Aldering, G.; Birchall, D.; Fakhouri, H.; Kim, A.; Nordin, J.; Nugent, P.; Perlmutter, S.; Runge, K.; Saunders, C.; Suzuki, N.; Pecontal, R. C. Thomas E.; Feindt, U.; Kowalski, M.; Benitez, S.; Hillebrandt, W.; Kromer, M.; Sasdelli, M.; Sternberg, A.; Taubenberger, S.

    2013-04-01

    The Nearby Supernova Factory II (http://snfactory.lbl.gov) reports the following spectroscopic observations of supernovae based on spectra (range 320-1000 nm) obtained with the SuperNova Integral Field Spectrograph (Aldering et al 2002, SPIE, 4836, 61) on the University of Hawaii 2.2-meter telescope. Classifications were performed using Superfit (Howell et al 2002, BAAS, 34, 1256) or SNID (Blondin & Tonry, 2007, ApJ, 666, 1024).

  18. Supernova 1987A in the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Kafatos, Minas; Michalitsianos, Andrew G.

    2006-11-01

    Foreword; Acknowledgements; Workshop participants; 1. Images and spectrograms of Sanduleak - 69º202, the SN 1987a progenitor N. R. Walborn; 2. The progenitor of SN 1987A G. Sonneborn; 3. Another supernova with a blue progenitor C. M. Gaskell and W. C. Keel; 4. Optical and infrared observations of SN 1987A from Cerro Tololo Inter-American Observatory M. M. Phillips; 5. SN 1987A: observational results obtained at ESO I. J. Danziger, P. Bouchet, R. A. E. Fosbury, C. Gouiffes, L. B. Lucy, A. F. M. Moorwood, E. Oliva and F. Rufener; 6. Observations of SN 1987A at the South African Astronomical Observatory (SAAO) M. W. Feast; 7. Observations of SN 1987A at the Anglo-Australian Telescope W. J. Couch; 8. Linear polarimetric study of SN 1987A A. Clocchiatti, M. Méndez, O. Benvenuto, C. Feinstein, H. Marraco, B. García and N. Morrell; 9. Infrared spectroscopy of SN 1987A from the NASA Kuiper Airborne Observatory H. P. Larson, S. Drapatz, M. J. Mumma and H. A. Weaver; 10. Radio observations of SN 1987A N. Bartel et al.; 11. Ultraviolet observations of SN 1987A: clues to mass loss R. P. Kirshner; 12. On the energetics of SN 1987A N. Panagia; 13. On the nature and apparent uniqueness of SN 1987A A. V. Filippenko; 14. A comparison of the SN 1987A light curve with other type II supernovae, and the detectability of similar supernovae M. F. Schmitz and C. M. Gaskell; 15. P-Cygni features and photospheric velocities L. Bildsten and J. C. L. Wang; 16. The Neutrino burst from SN 1987A detected in the Mont Blanc LSD experiment M. Aglietta et al.; 17. Toward observational neutrino astrophysics M. Koshiba; 18. The discovery of neutrinos from SN 1987A with the IMB detector J. Matthews; 19. Peering into the abyss: the neutrinos from SN 1987A A. Burrows; 20. Phenomenological analysis of neutrino emission from SN 1987A J. N. Bahcall, D. N. Spergel and W. H. Press; 21. Mass determination of neutrinos H. Y. Chiu; 22. Neutrino transport in a type II supernova D. C. Ellison, P. M. Giovanoni

  19. TYPE Ia SUPERNOVA PROPERTIES AS A FUNCTION OF THE DISTANCE TO THE HOST GALAXY IN THE SDSS-II SN SURVEY

    SciTech Connect

    Galbany, Lluis; Miquel, Ramon; Oestman, Linda; Brown, Peter J.; Olmstead, Matthew D.; Cinabro, David; D'Andrea, Chris B.; Nichol, Robert C.; Frieman, Joshua; Jha, Saurabh W.; Marriner, John; Nordin, Jakob; Sako, Masao; Schneider, Donald P.; Smith, Mathew; Sollerman, Jesper; Pan, Kaike; Snedden, Stephanie; Bizyaev, Dmitry; Brewington, Howard; and others

    2012-08-20

    We use Type Ia supernovae (SNe Ia) discovered by the Sloan Digital Sky Survey-II SN Survey to search for dependencies between SN Ia properties and the projected distance to the host-galaxy center, using the distance as a proxy for local galaxy properties (local star formation rate, local metallicity, etc.). The sample consists of almost 200 spectroscopically or photometrically confirmed SNe Ia at redshifts below 0.25. The sample is split into two groups depending on the morphology of the host galaxy. We fit light curves using both MLCS2K2 and SALT2, and determine color (A{sub V} , c) and light-curve shape ({Delta}, x{sub 1}) parameters for each SN Ia, as well as its residual in the Hubble diagram. We then correlate these parameters with both the physical and the normalized distances to the center of the host galaxy and look for trends in the mean values and scatters of these parameters with increasing distance. The most significant (at the 4{sigma} level) finding is that the average fitted A{sub V} from MLCS2K2 and c from SALT2 decrease with the projected distance for SNe Ia in spiral galaxies. We also find indications that supernovae (SNe) in elliptical galaxies tend to have narrower light curves if they explode at larger distances, although this may be due to selection effects in our sample. We do not find strong correlations between the residuals of the distance moduli with respect to the Hubble flow and the galactocentric distances, which indicates a limited correlation between SN magnitudes after standardization and local host metallicity.

  20. Revised Lens Model and Predictions of Time Delay for the Multiply Imaged Lensed Supernova, “SN Refsdal”, in the FF cluster MACS J1149+2223

    NASA Astrophysics Data System (ADS)

    Sharon, Keren; Johnson, Traci Lin

    2015-08-01

    We present a revised lens model of MACS J1149+2223, in which the first resolved multiply imaged lensed supernova (SN) was discovered. The lens model is based on the model of Johnson et al. with some modifications. We include more lensing constraints from the host galaxy of the newly discovered SN, and increase the flexibility of the model in order to better reproduce the lensing signal in the vicinity of this galaxy. The revised model accurately reconstructs the positions of the lensed SN, provides magnifications, predicts the time delay between the instances of the SN, and derive their uncertainties. We find that the time delays between the four observed images are a few days: t(S2) = 2 +10/-6 days, t(S3)=-5 +13/-7 days, t(S4)=7 +16/-3 days. At the positions of the other images of the same host galaxy, an image of the SN had appeared on the opposite side of the cluster some 11-13 years ago, and another is predicted to appear approximately 180-280 days after S1, i.e., in a 3-month window around July 2015. This image will be less magnified than the ones already detected, with magnification of mu=5 (compared to mu~10-20 of the four images that were observed in 2014, making it about three times fainter). Finally, we reconstruct the source image of the host galaxy, and position the SN on one of its spiral arms. New lensing constraints from the full depth FF imaging will improve the accuracy of future lens models. Products of this lens model are available to the community through MAST.

  1. KECK OBSERVATIONS OF THE YOUNG METAL-POOR HOST GALAXY OF THE SUPER-CHANDRASEKHAR-MASS TYPE Ia SUPERNOVA SN 2007if

    SciTech Connect

    Childress, M.; Aldering, G.; Aragon, C.; Bailey, S.; Fakhouri, H. K.; Hsiao, E. Y.; Loken, S.; Antilogus, P.; Bongard, S.; Canto, A.; Pain, R.; Baltay, C.; Buton, C.; Kerschhaggl, M.; Kowalski, M.; Paech, K.; Chotard, N.; Copin, Y.; Gangler, E.

    2011-05-20

    We present Keck LRIS spectroscopy and g-band photometry of the metal-poor, low-luminosity host galaxy of the super-Chandrasekhar-mass Type Ia supernova SN 2007if. Deep imaging of the host reveals its apparent magnitude to be m{sub g} = 23.15 {+-} 0.06, which at the spectroscopically measured redshift of z{sub helio} = 0.07450 {+-} 0.00015 corresponds to an absolute magnitude of M{sub g} = -14.45 {+-} 0.06. Galaxy g - r color constrains the mass-to-light ratio, giving a host stellar mass estimate of log(M{sub *}/M{sub sun}) = 7.32 {+-} 0.17. Balmer absorption in the stellar continuum, along with the strength of the 4000 A break, constrains the age of the dominant starburst in the galaxy to be t{sub burst} = 123{sup +165}{sub -77} Myr, corresponding to a main-sequence turnoff mass of M/M{sub sun} = 4.6{sup +2.6}{sub -1.4}. Using the R{sub 23} method of calculating metallicity from the fluxes of strong emission lines, we determine the host oxygen abundance to be 12 + log(O/H){sub KK04} = 8.01 {+-} 0.09, significantly lower than any previously reported spectroscopically measured Type Ia supernova host galaxy metallicity. Our data show that SN 2007if is very likely to have originated from a young, metal-poor progenitor.

  2. Early-time spectra of supernovae and their precursor winds. The luminous blue variable/yellow hypergiant progenitor of SN 2013cu

    NASA Astrophysics Data System (ADS)

    Groh, Jose H.

    2014-12-01

    We present the first quantitative spectroscopic modeling of an early-time supernova (SN) that interacts with its progenitor wind. Using the radiative transfer code CMFGEN, we investigate the recently reported 15.5 h post-explosion spectrum of the type IIb SN 2013cu. We are able to directly measure the chemical abundances of a SN progenitor and find a relatively H-rich wind, with H and He abundances (by mass) of X = 0.46 ± 0.2 and Y = 0.52 ± 0.2, respectively. The wind is enhanced in N and depleted in C relative to solar values (mass fractions of 8.2 × 10-3 and 1.0 × 10-5, respectively). We obtain that a slow, dense wind or circumstellar medium surrounds the precursor at the pre-SN stage, with a wind terminal velocity vwind ≲ 100 km s-1 and mass-loss rate of Ṁ ≃ 3 × 10-3 (vwind/ 100 km s-1) M⊙ yr-1. These values are lower than previous analytical estimates, although Ṁ/υ∞ is consistent with previous work. We also compute a CMFGEN model to constrain the progenitor spectral type; the high Ṁ and low vwind imply that the star had an effective temperature of ≃ 8000 K immediately before the SN explosion. Our models suggest that the progenitor was either an unstable luminous blue variable or a yellow hypergiant undergoing an eruptive phase, and rule out a Wolf-Rayet star. We classify the post-explosion spectra at 15.5 h as XWN5(h) and advocate for the use of the prefix "X" (eXplosion) to avoid confusion between post-explosion, non-stellar spectra, and those of massive stars. We show that the XWN spectrum results from the ionization of the progenitor wind after the SN, and that the progenitor spectral type is significantly different from the early post-explosion spectral type owing to the huge differences in the ionization structure before and after the SN event. We find the following temporal evolution: LBV/YHG → XWN5(h) → SN IIb. Future early-time spectroscopy in the UV will further constrain the properties of SN precursors, such as their

  3. THE BROAD-LINED Type Ic SN 2012ap AND THE NATURE OF RELATIVISTIC SUPERNOVAE LACKING A GAMMA-RAY BURST DETECTION

    SciTech Connect

    Milisavljevic, D.; Margutti, R.; Parrent, J. T.; Soderberg, A. M.; Sanders, N. E.; Kamble, A.; Chakraborti, S.; Drout, M. R.; Kirshner, R. P.; Fesen, R. A.; Mazzali, P.; Maeda, K.; Cenko, S. B.; Silverman, J. M.; Filippenko, A. V.; Pickering, T. E.; Kawabata, K.; Hattori, T.; Hsiao, E. Y.; Stritzinger, M. D.; and others

    2015-01-20

    We present ultraviolet, optical, and near-infrared observations of SN 2012ap, a broad-lined Type Ic supernova in the galaxy NGC 1729 that produced a relativistic and rapidly decelerating outflow without a gamma-ray burst signature. Photometry and spectroscopy follow the flux evolution from –13 to +272 days past the B-band maximum of –17.4 ± 0.5 mag. The spectra are dominated by Fe II, O I, and Ca II absorption lines at ejecta velocities of v ≈ 20,000 km s{sup –1} that change slowly over time. Other spectral absorption lines are consistent with contributions from photospheric He I, and hydrogen may also be present at higher velocities (v ≳ 27,000 km s{sup –1}). We use these observations to estimate explosion properties and derive a total ejecta mass of ∼2.7 M {sub ☉}, a kinetic energy of ∼1.0 × 10{sup 52} erg, and a {sup 56}Ni mass of 0.1-0.2 M {sub ☉}. Nebular spectra (t > 200 days) exhibit an asymmetric double-peaked [O I] λλ6300, 6364 emission profile that we associate with absorption in the supernova interior, although toroidal ejecta geometry is an alternative explanation. SN 2012ap joins SN 2009bb as another exceptional supernova that shows evidence for a central engine (e.g., black hole accretion or magnetar) capable of launching a non-negligible portion of ejecta to relativistic velocities without a coincident gamma-ray burst detection. Defining attributes of their progenitor systems may be related to notable observed properties including environmental metallicities of Z ≳ Z {sub ☉}, moderate to high levels of host galaxy extinction (E(B – V) > 0.4 mag), detection of high-velocity helium at early epochs, and a high relative flux ratio of [Ca II]/[O I] >1 at nebular epochs. These events support the notion that jet activity at various energy scales may be present in a wide range of supernovae.

  4. The Broad-lined Type Ic SN 2012ap and the Nature of Relativistic Supernovae Lacking a Gamma-Ray Burst Detection

    NASA Astrophysics Data System (ADS)

    Milisavljevic, D.; Margutti, R.; Parrent, J. T.; Soderberg, A. M.; Fesen, R. A.; Mazzali, P.; Maeda, K.; Sanders, N. E.; Cenko, S. B.; Silverman, J. M.; Filippenko, A. V.; Kamble, A.; Chakraborti, S.; Drout, M. R.; Kirshner, R. P.; Pickering, T. E.; Kawabata, K.; Hattori, T.; Hsiao, E. Y.; Stritzinger, M. D.; Marion, G. H.; Vinko, J.; Wheeler, J. C.

    2015-01-01

    We present ultraviolet, optical, and near-infrared observations of SN 2012ap, a broad-lined Type Ic supernova in the galaxy NGC 1729 that produced a relativistic and rapidly decelerating outflow without a gamma-ray burst signature. Photometry and spectroscopy follow the flux evolution from -13 to +272 days past the B-band maximum of -17.4 ± 0.5 mag. The spectra are dominated by Fe II, O I, and Ca II absorption lines at ejecta velocities of v ≈ 20,000 km s-1 that change slowly over time. Other spectral absorption lines are consistent with contributions from photospheric He I, and hydrogen may also be present at higher velocities (v >~ 27,000 km s-1). We use these observations to estimate explosion properties and derive a total ejecta mass of ~2.7 M ⊙, a kinetic energy of ~1.0 × 1052 erg, and a 56Ni mass of 0.1-0.2 M ⊙. Nebular spectra (t > 200 days) exhibit an asymmetric double-peaked [O I] λλ6300, 6364 emission profile that we associate with absorption in the supernova interior, although toroidal ejecta geometry is an alternative explanation. SN 2012ap joins SN 2009bb as another exceptional supernova that shows evidence for a central engine (e.g., black hole accretion or magnetar) capable of launching a non-negligible portion of ejecta to relativistic velocities without a coincident gamma-ray burst detection. Defining attributes of their progenitor systems may be related to notable observed properties including environmental metallicities of Z >~ Z ⊙, moderate to high levels of host galaxy extinction (E(B - V) > 0.4 mag), detection of high-velocity helium at early epochs, and a high relative flux ratio of [Ca II]/[O I] >1 at nebular epochs. These events support the notion that jet activity at various energy scales may be present in a wide range of supernovae.

  5. The Broad-Lined Type Ic SN 2012ap and the Nature of Relativistic Supernovae Lacking a Gamma-Ray Burst Detection

    NASA Technical Reports Server (NTRS)

    Milisavljevic, D.; Margutti, R.; Parrent, J. T.; Soderberg, A. M.; Fesen, R. A.; Mazzali, P.; Maeda, K.; Sanders, N. E.; Cenko, S. B.; Silverman, J. M.

    2014-01-01

    We present ultraviolet, optical, and near-infrared observations of SN2012ap, a broad-lined Type Ic supernova in the galaxy NGC 1729 that produced a relativistic and rapidly decelerating outflow without a gamma-ray burst signature. Photometry and spectroscopy follow the flux evolution from -13 to +272 days past the B-band maximum of -17.4 +/- 0.5 mag. The spectra are dominated by Fe II, O I, and Ca II absorption lines at ejecta velocities of v approx. 20,000 km s(exp. -1) that change slowly over time. Other spectral absorption lines are consistent with contributions from photospheric He I, and hydrogen may also be present at higher velocities (v approx. greater than 27,000 km s(exp. -1)). We use these observations to estimate explosion properties and derive a total ejecta mass of 2.7 Solar mass, a kinetic energy of 1.0×1052 erg, and a (56)Ni mass of 0.1-0.2 Solar mass. Nebular spectra (t > 200 d) exhibit an asymmetric double-peaked [O I] lambda lambda 6300, 6364 emission profile that we associate with absorption in the supernova interior, although toroidal ejecta geometry is an alternative explanation. SN2012ap joins SN2009bb as another exceptional supernova that shows evidence for a central engine (e.g., black-hole accretion or magnetar) capable of launching a non-negligible portion of ejecta to relativistic velocities without a coincident gamma-ray burst detection. Defining attributes of their progenitor systems may be related to notable properties including above-average environmental metallicities of Z approx. greater than Solar Z, moderate to high levels of host-galaxy extinction (E(B -V ) > 0.4 mag), detection of high-velocity helium at early epochs, and a high relative flux ratio of [Ca II]/[O I] > 1 at nebular epochs. These events support the notion that jet activity at various energy scales may be present in a wide range of supernovae.

  6. Optical and near-infrared observations of SN 2014ck: an outlier among the Type Iax supernovae

    NASA Astrophysics Data System (ADS)

    Tomasella, L.; Cappellaro, E.; Benetti, S.; Pastorello, A.; Hsiao, E. Y.; Sand, D. J.; Stritzinger, M.; Valenti, S.; McCully, C.; Arcavi, I.; Elias-Rosa, N.; Harmanen, J.; Harutyunyan, A.; Hosseinzadeh, G.; Howell, D. A.; Kankare, E.; Morales-Garoffolo, A.; Taddia, F.; Tartaglia, L.; Terreran, G.; Turatto, M.

    2016-06-01

    We present a comprehensive set of optical and near-infrared (NIR) photometric and spectroscopic observations for SN 2014ck, extending from pre-maximum to six months later. These data indicate that SN 2014ck is photometrically nearly identical to SN 2002cx, which is the prototype of the class of peculiar transients named SNe Iax. Similar to SN 2002cx, SN 2014ck reached a peak brightness MB = -17.37 ± 0.15 mag, with a post-maximum decline rate Δm15(B) = 1.76 ± 0.15 mag. However, the spectroscopic sequence shows similarities with SN 2008ha, which was three magnitudes fainter and faster declining. In particular, SN 2014ck exhibits extremely low ejecta velocities, ˜3000 km s-1 at maximum, which are close to the value measured for SN 2008ha and half the value inferred for SN 2002cx. The bolometric light curve of SN 2014ck is consistent with the production of 0.10^{+0.04}_{-0.03} M_{{⊙}} of 56Ni. The spectral identification of several iron-peak features, in particular Co II lines in the NIR, provides a clear link to SNe Ia. Also, the detection of narrow Si, S and C features in the pre-maximum spectra suggests a thermonuclear explosion mechanism. The late-phase spectra show a complex overlap of both permitted and forbidden Fe, Ca and Co lines. The appearance of strong [Ca II] λλ7292, 7324 again mirrors the late-time spectra of SN 2008ha and SN 2002cx. The photometric resemblance to SN 2002cx and the spectral similarities to SN 2008ha highlight the peculiarity of SN 2014ck, and the complexity and heterogeneity of the SNe Iax class.

  7. Expectations for the hard x-ray continuum and gamma-ray line fluxes from the typE IA supernova SN 2014J in M82

    SciTech Connect

    The, Lih-Sin; Burrows, Adam E-mail: burrows@astro.princeton.edu

    2014-05-10

    The hard X-ray continuum and gamma-ray lines from a Type Ia supernova dominate its integrated photon emissions and can provide unique diagnostics of the mass of the ejecta, the {sup 56}Ni yield and spatial distribution, its kinetic energy and expansion speed, and the mechanism of explosion. Such signatures and their time behavior 'X-ray' the bulk debris field in direct fashion, and do not depend on the ofttimes problematic and elaborate UV, optical, and near-infrared spectroscopy and radiative transfer that have informed the study of these events for decades. However, to date no hard photons have ever been detected from a Type Ia supernova in explosion. With the advent of the supernova SN 2014J in M82, at a distance of ∼3.5 Mpc, this situation may soon change. Both NuSTAR and INTEGRAL have the potential to detect SN 2014J, and, if spectra and light curves can be measured, would usefully constrain the various explosion models published during the last ∼30 yr. In support of these observational campaigns, we provide predictions for the hard X-ray continuum and gamma-line emissions for 15 Type Ia explosion models gleaned from the literature. The model set, containing as it does deflagration, delayed detonation, merger detonation, pulsational delayed detonation, and sub-Chandrasekhar helium detonation models, collectively spans a wide range of properties, and hence signatures. We provide a brief discussion of various diagnostics (with examples), but importantly make the spectral and line results available electronically to aid in the interpretation of the anticipated data.

  8. Expectations for the Hard X-Ray Continuum and Gamma-Ray Line Fluxes from the Type Ia Supernova SN 2014J in M82

    NASA Astrophysics Data System (ADS)

    The, Lih-Sin; Burrows, Adam

    2014-05-01

    The hard X-ray continuum and gamma-ray lines from a Type Ia supernova dominate its integrated photon emissions and can provide unique diagnostics of the mass of the ejecta, the 56Ni yield and spatial distribution, its kinetic energy and expansion speed, and the mechanism of explosion. Such signatures and their time behavior "X-ray" the bulk debris field in direct fashion, and do not depend on the ofttimes problematic and elaborate UV, optical, and near-infrared spectroscopy and radiative transfer that have informed the study of these events for decades. However, to date no hard photons have ever been detected from a Type Ia supernova in explosion. With the advent of the supernova SN 2014J in M82, at a distance of ~3.5 Mpc, this situation may soon change. Both NuSTAR and INTEGRAL have the potential to detect SN 2014J, and, if spectra and light curves can be measured, would usefully constrain the various explosion models published during the last ~30 yr. In support of these observational campaigns, we provide predictions for the hard X-ray continuum and gamma-line emissions for 15 Type Ia explosion models gleaned from the literature. The model set, containing as it does deflagration, delayed detonation, merger detonation, pulsational delayed detonation, and sub-Chandrasekhar helium detonation models, collectively spans a wide range of properties, and hence signatures. We provide a brief discussion of various diagnostics (with examples), but importantly make the spectral and line results available electronically to aid in the interpretation of the anticipated data.

  9. HUBBLE PINPOINTS DISTANT SUPERNOVAE

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These Hubble Space Telescope images pinpoint three distant supernovae, which exploded and died billions of years ago. Scientists are using these faraway light sources to estimate if the universe was expanding at a faster rate long ago and is now slowing down. Images of SN 1997cj are in the left hand column; SN 1997ce, in the middle; and SN 1997ck, on the right. All images were taken by the Hubble telescope's Wide Field and Planetary Camera 2. The top row of images are wider views of the supernovae. The supernovae were discovered in April 1997 in a ground-based survey at the Canada-France-Hawaii Telescope on Mauna Kea, Hawaii. Once the supernovae were discovered, the Hubble telescope was used to distinguish the supernovae from the light of their host galaxies. A series of Hubble telescope images were taken in May and June 1997 as the supernovae faded. Six Hubble telescope observations spanning five weeks were taken for each supernova. This time series enabled scientists to measure the brightness and create a light curve. Scientists then used the light curve to make an accurate estimate of the distances to the supernovae. Scientists combined the estimated distance with the measured velocity of the supernova's host galaxy to determine the expansion rate of the universe in the past (5 to 7 billion years ago) and compare it with the current rate. These supernovae belong to a class called Type Ia, which are considered reliable distance indicators. Looking at great distances also means looking back in time because of the finite velocity of light. SN 1997ck exploded when the universe was half its present age. It is the most distant supernova ever discovered (at a redshift of 0.97), erupting 7.7 billion years ago. The two other supernovae exploded about 5 billion years ago. SN 1997ce has a redshift of 0.44; SN 1997cj, 0.50. SN 1997ck is in the constellation Hercules, SN 1997ce is in Lynx, just north of Gemini; and SN 1997cj is in Ursa Major, near the Hubble Deep Field

  10. Light-travel-time diagnostics in early supernova spectra: substantial mass-loss of the IIb progenitor of SN 2013cu through a superwind

    NASA Astrophysics Data System (ADS)

    Gräfener, G.; Vink, J. S.

    2016-01-01

    The progenitors of Type-IIb supernovae (SNe IIb) are believed to have lost their H-rich envelopes almost completely in the direct pre-SN phase. Recently the first `flash spectrum' of an SN IIb (SN 2013cu) has been presented, taken early enough to study its immediate circumstellar medium (CSM). Similar to a previous study by Groh, we analyse the structure and chemical composition of the optically thick CSM using non-local thermodynamic equilibrium(non-LTE) model atmospheres. For the first time, we take light-travel time effects on the spectrum formation into account, which affect the shapes and strengths of the observable emission lines, as well as the inferred SN luminosity. Based on the new CSM parameters, we estimate a lower limit of ˜0.3 M⊙ for the CSM mass, which is a factor 10-100 higher than previous estimates. The spectral fit implies a CSM in the form of a homogeneous and spherically symmetric superwind whose mass-loss rate exceeds common expectations by up to two orders of magnitude. The derived chemical composition is in agreement with a progenitor that has just left, or is just about to leave the Red-Supergiant stage, confirming the standard picture for the origin of SNe IIb. Due to its extreme mass-loss, the SN progenitor will likely appear as extreme RSG, Luminous Blue Variable, or Yellow Hypergiant. The direct detection of a superwind, and the high inferred CSM mass suggest that stellar wind mass-loss may play an important role in the formation of SNe IIb.

  11. Progenitors of supernova Ibc: a single Wolf-Rayet star as the possible progenitor of the SN Ib iPTF13bvn

    NASA Astrophysics Data System (ADS)

    Groh, Jose H.; Georgy, Cyril; Ekström, Sylvia

    2013-10-01

    Core-collapse supernova (SN) explosions mark the end of the tumultuous life of massive stars. Determining the nature of their progenitors is a crucial step towards understanding the properties of SNe. Until recently, no progenitor has been directly detected for SN of type Ibc, which are believed to come from massive stars that lose their hydrogen envelope through stellar winds and from binary systems where the companion has stripped the H envelope from the primary. Here we analyze recently reported observations of iPTF13bvn, which could possibly be the first detection of a SN Ib progenitor based on pre-explosion images. Very interestingly, the recently published Geneva models of single stars can reproduce the observed photometry of the progenitor candidate and its mass-loss rate, confirming a recently proposed scenario. We find that a single WR star with initial mass in the range 31-35 M⊙ fits the observed photometry of the progenitor of iPTF13bvn. The progenitor likely has a luminosity of log (L⋆/L⊙) ~ 5.55, surface temperature ~45 000 K, and mass of ~10.9 M⊙ at the time of explosion. Our non-rotating 32 M⊙ model overestimates the derived radius of the progenitor, although this could likely be reconciled with a fine-tuned model of a more massive (between 40 and 50 M⊙), hotter, and luminous progenitor. Our models indicate a very uncertain ejecta mass of ~8 M⊙, which is higher than the average of the SN Ib ejecta mass that is derived from the lightcurve (2-4 M⊙). This possibly high ejecta mass could produce detectable effects in the iPTF13bvn lightcurve and spectrum. If the candidate is indeed confirmed to be the progenitor, our results suggest that stars with relatively high initial masses (> 30 M⊙) can produce visible SN explosions at their deaths and do not collapse directly to a black hole.

  12. Turbulence in Type Ia Supernovae Simulations

    NASA Astrophysics Data System (ADS)

    Fisher, Robert

    2012-03-01

    Type Ia supernovae are among the most energetic explosions in the known universe, releasing 10^51 ergs of kinetic energy in their ejecta, with 0.7 solar masses of radioactive Ni-56 synthesized during the explosion. The discovery of the Phillips relation enabled the use of Type Ia supernova (SN Ia) as standardizable cosmological candles, and has ushered in a new era of astronomy leading to the discovery of the acceleration of the universe, leading to the 2011 Nobel Prize in physics. The nature of the Type Ia progenitors, as well as their precise explosion mechanism, remains a subject of active investigation, both observationally as well as theoretically. It is known that the progenitors of Type Ia supernovae are near-Chandrasekhar mass white dwarfs in binary systems, though competing models suggest the companion is either a red giant or main sequence star (the so-called ``single-degenerate channel'') or another white dwarf (the ``double-degenerate channel''). In this talk, I will present recent results of three -dimensional models of the single-degenerate channel of Type Ia supernovae. I will also discuss prospects for modeling the double-degenerate channel of Type Ia supernovae, which have recently enjoyed increased favor from observers and theorists.

  13. BORON SYNTHESIS IN TYPE Ic SUPERNOVAE

    SciTech Connect

    Nakamura, Ko; Kajino, Toshitaka; Yoshida, Takashi; Shigeyama, Toshikazu

    2010-08-01

    We investigate the {nu}-process in an energetic Type Ic supernova (SN Ic) and the resultant productions of the light elements including boron and its stable isotopes. SN Ic is a very unique boron source because it can produce boron not only through spallation reactions as discussed in Nakamura and Shigeyama but also the {nu}-process. The {nu}-process is considered to occur in core-collapse supernovae and previous studies were limited to SNe II. Although the progenitor star of an SN Ic does not posses an He envelope so that {sup 7}Li production via the {nu}-process is unlikely, {sup 11}B can be produced in the C-rich layers. We demonstrate a hydrodynamic simulation of a SN Ic explosion and estimate the amounts of the light elements produced via the {nu}-process for the first time, and also the subsequent spallation reactions between the outermost layers of the compact SN Ic progenitor and the ambient medium. We find that the {nu}-process in the current SN Ic model produces a significant amount of {sup 11}B, which is diluted by {sup 10}B from spallation reactions to get closer to B isotopic ratios observed in meteorites. We also confirm that high-temperature {mu} and {tau} neutrinos and their anti-neutrinos, reasonably suggested from the compact structure of SN Ic progenitors, enhance the light-element production through the neutral current reactions, which may imply an important role of SNe Ic in the Galactic chemical evolution.

  14. Type Ia Supernova Properties as a Function of the Distance to the Host Galaxy in the SDSS-II SN Survey

    SciTech Connect

    Galbany, Lluis; et al.

    2012-08-20

    We use type-Ia supernovae (SNe Ia) discovered by the SDSS-II SN Survey to search for dependencies between SN Ia properties and the projected distance to the host galaxy center, using the distance as a proxy for local galaxy properties (local star-formation rate, local metallicity, etc.). The sample consists of almost 200 spectroscopically or photometrically confirmed SNe Ia at redshifts below 0.25. The sample is split into two groups depending on the morphology of the host galaxy. We fit light-curves using both MLCS2k2 and SALT2, and determine color (AV, c) and light-curve shape (delta, x1) parameters for each SN Ia, as well as its residual in the Hubble diagram. We then correlate these parameters with both the physical and the normalized distances to the center of the host galaxy and look for trends in the mean values and scatters of these parameters with increasing distance. The most significant (at the 4-sigma level) finding is that the average fitted AV from MLCS2k2 and c from SALT2 decrease with the projected distance for SNe Ia in spiral galaxies. We also find indications that SNe in elliptical galaxies tend to have narrower light-curves if they explode at larger distances, although this may be due to selection effects in our sample. We do not find strong correlations between the residuals of the distance moduli with respect to the Hubble flow and the galactocentric distances, which indicates a limited correlation between SN magnitudes after standardization and local host metallicity.

  15. A Study of SN Ejecta in the Core-Collapse Supernova Remnant G292.0+1.8: Cas A's Older Cousin

    NASA Astrophysics Data System (ADS)

    Fesen, Robert

    2006-07-01

    Recent studies of the southern oxygen-rich supernova remnant {SNR} G292.0+1.8 have shown it to be the only Galactic SNR to exhibit all the features we expect in young remnants of core-collapse supernovae: an outer shell behind an expanding primary shock, high-velocity fragments of undiluted metal-rich ejecta, and a central pulsar surrounded by a pulsar-wind nebula. G292.0+1.8's optical emission consists of numerous knots and filaments of O- and S-rich ejecta spread throughout much of the remnant shell, many with radially oriented pencil-like geometries that may trace their origins to Rayleigh-Taylor instabilities during the SN event. The evolution and fine-scale structure of SN debris in young remnants is poorly understood and largely uncharted territory. For testing models for the distribution of metal-rich ejecta from core-collapse SNe, how the ejecta evolve and clump, and how SN shocks interact with the local circumstellar medium, the 3000-yr-old G292.0+1.8 remnant rivals the 320-yr-old Cas A remnant in importance. We therefore propose the first HST images of G292.0+1.8 in order to characterize the fine-scale spatial distribution of the ejecta, their sub-arcsecond chemical make-up, and the detailed structure and scale lengths for metal-rich SN ejecta clumps. The proposed HST images of G292.0+1.8 will be used in conjunction with existing Spitzer Cycle 1 infrared data and an upcoming 0.5 Msec Chandra X-ray image. We expect to achieve the same kind of results for G292 that have already been obtained for Cas A. High-resolution HST images of this remnant, combined with Spitzer and Chandra data and contrasted with a similar data set on Cas A, will provide superb multiwavelength benchmarks for both very young and older core-collapse SNRs.

  16. The environment of the rarest and most energetic supernovae: do pair-instability explosions exist in the nearby Universe?

    NASA Astrophysics Data System (ADS)

    De Cia, Annalisa

    2014-10-01

    We propose imaging of the host galaxies of super-luminous supernovae (SLSNe) of the rarest class, SLSN-R. These SNe are several magnitudes brighter than typical core-collapse SNe and their late-time light curves follow the 56Co radioactive decay. The physical process that leads to their explosion is under debate. Observationally, the more likely possibility is that SLSN-R are the product of stars with cores more massive than several tens of solar masses, that explode due to pair-production instability. However, such pair instability supernovae (PISNe) are theoretically easier to form from zero-metallicity population III stars at high redshifts, that could develop the massive cores required. Local pockets of low-metallicity gas or highly dense stellar clusters may allow PISNe to form at low redshift, but this has not been observationally confirmed. Our pilot HST program targeting a single SLSN-R (PTF10nmn) surprisingly showed it occurred well away from the host's most intense star formation, in a lower-metallicity region, up to 10 times lower than would have been measured using ground-based data alone. Here, we propose to target 4 additional SLSNe-R (out of a total of 6 events), all nearby candidate PISNe homogeneously selected from the Palomar Transient Factory wide-field survey, among thousands of classified SNe. The accurate location of these SNe with respect to their host galaxies and star-forming regions can provide invaluable information on the (typical?) environment of these events. This is crucial to both address the question of the existence of PISNe in the nearby Universe and to investigate the physical nature of these rare, extreme and debated explosions.

  17. Swift Observations of Supernovae during and after Shock Breakout

    NASA Technical Reports Server (NTRS)

    Immler, Stefan

    2008-01-01

    Over the past few years, space-based observatories have allowed detailed studies of energetic supernova explosions in previously unexplored time domains and wavelength regimes. NASA's Swift observatory is playing an important role in probing the early emission of SNe during and after shock breakout due to its fast response, flexible scheduling capabilities, and large wavelength band coverage, ranging from the optical, W, and X-ray to the Gamma-ray bands. By studying the outgoing SN shocks with material in its surroundings, the explosion physics and nature of progenitor stars can be studied. Furthermore, monitoring the X-ray emission of SNe with space-based X-ray observatories is being used to map the density structure in SN environments out to large radii from the sites of the explosions (>E20 cm), the transition of a SN into an old supernova remnant can be studied, and the mass-loss rates of the progenitor stars are being probed over significant timescales (>E4 years) in the stellar wind history. In combination, these observations give unprecedented insights into the nature of energetic explosions and their environments. During this talk, I will present highlights from recent observations, among them the first observation of a SN DURING the actual explosion with Swift, and I will discuss the "naked eye" burst at a redshift of -1, which was the most distant object humans could ever see with their own eyes.

  18. Atomic and molecular supernovae

    SciTech Connect

    Liu, W.

    1997-12-01

    Atomic and molecular physics of supernovae is discussed with an emphasis on the importance of detailed treatments of the critical atomic and molecular processes with the best available atomic and molecular data. The observations of molecules in SN 1987A are interpreted through a combination of spectral and chemical modelings, leading to strong constraints on the mixing and nucleosynthesis of the supernova. The non-equilibrium chemistry is used to argue that carbon dust can form in the oxygen-rich clumps where the efficient molecular cooling makes the nucleation of dust grains possible. For Type Ia supernovae, the analyses of their nebular spectra lead to strong constraints on the supernova explosion models.

  19. Atomic and molecular supernovae

    NASA Technical Reports Server (NTRS)

    Liu, Weihong

    1997-01-01

    Atomic and molecular physics of supernovae is discussed with an emphasis on the importance of detailed treatments of the critical atomic and molecular processes with the best available atomic and molecular data. The observations of molecules in SN 1987A are interpreted through a combination of spectral and chemical modelings, leading to strong constraints on the mixing and nucleosynthesis of the supernova. The non-equilibrium chemistry is used to argue that carbon dust can form in the oxygen-rich clumps where the efficient molecular cooling makes the nucleation of dust grains possible. For Type Ia supernovae, the analyses of their nebular spectra lead to strong constraints on the supernova explosion models.

  20. Supernova and cosmic rays

    NASA Technical Reports Server (NTRS)

    Wefel, J. P.

    1981-01-01

    A general overview of supernova astronomy is presented, followed by a discussion of the relationship between SN and galactic cosmic rays. Pre-supernova evolution is traced to core collapse, explosion, and mass ejection. The two types of SN light curves are discussed in terms of their causes, and the different nucleosynthetic processes inside SNs are reviewed. Physical events in SN remnants are discussed. The three main connections between cosmic rays and SNs, the energy requirement, the acceleration mechanism, and the detailed composition of CR, are detailed.

  1. Nature of type 1 Supernovae

    NASA Technical Reports Server (NTRS)

    Shklovskiy, I. S.

    1980-01-01

    The nature of type 1 supernovae (SN 1) is discussed through a comparison of observational evidence and theoretical perspectives relating to both type 1 and 2 supernovae. In particular two hypotheses relating to SN 1 phenomenon are examined: the first proposing that SN 1 are components of binary systems in which, at a comparatively late stage of evolution, overflow of the mass occurs; the second considers pre-SN 1 to be recently evolved stars with a mass greater than 1.4 solar mass (white dwarfs). In addition, an explanation of the reduced frequency of flares of SN 1 in spiral galaxies as related to that in elliptical galaxies is presented.

  2. A High-Resolution X-Ray and Optical Study of SN1006: Asymmetric Expansion and Small-Scale Structure in a Type Ia Supernova Remnant

    NASA Technical Reports Server (NTRS)

    Winkler, P. Frank; Williams, Brian J.; Reynolds, Stephen P.; Petre, Robert; Long, Knox S.; Katsuda, Satoru; Hwang, Una

    2014-01-01

    We introduce a deep (670 ks) X-ray survey of the entire SN 1006 remnant from the Chandra X-Ray Observatory, together with a deep Ha image of SN 1006 from the 4 m Blanco telescope at CTIO. Comparison with Chandra images from 2003 gives the first measurement of the X-ray proper motions around the entire periphery, carried out over a 9 yr baseline. We find that the expansion velocity varies significantly with azimuth. The highest velocity of approx.7400 km/s (almost 2.5 times that in the northwest (NW)) is found along the southeast (SE) periphery, where both the kinematics and the spectra indicate that most of the X-ray emission stems from ejecta that have been decelerated little, if at all. Asymmetries in the distribution of ejecta are seen on a variety of spatial scales. Si-rich ejecta are especially prominent in the SE quadrant, while O and Mg are more uniformly distributed, indicating large-scale asymmetries arising from the explosion itself. Neon emission is strongest in a sharp filament just behind the primary shock along the NWrim, where the pre-shock density is highest. Here the Ne is likely interstellar, while Ne within the shell may include a contribution from ejecta. Within the interior of the projected shell we find a few isolated "bullets" of what appear to be supernova ejecta that are immediately preceded by bowshocks seen in Ha, features that we interpret as ejecta knots that have reached relatively dense regions of the surrounding interstellar medium, but that appear in the interior in projection. Recent three-dimensional hydrodynamic models for Type Ia supernovae display small-scale features that strongly resemble the ones seen in X-rays in SN 1006; an origin in the explosion itself or from subsequent hydrodynamic instabilities both remain viable options. We have expanded the search for precursor X-ray emission ahead of a synchrotron-dominated shock front, as expected from diffusive shock acceleration theory, to numerous regions along both the

  3. A High-resolution X-Ray and Optical Study of SN 1006: Asymmetric Expansion and Small-scale Structure in a Type Ia Supernova Remnant

    NASA Astrophysics Data System (ADS)

    Winkler, P. Frank; Williams, Brian J.; Reynolds, Stephen P.; Petre, Robert; Long, Knox S.; Katsuda, Satoru; Hwang, Una

    2014-02-01

    We introduce a deep (670 ks) X-ray survey of the entire SN 1006 remnant from the Chandra X-Ray Observatory, together with a deep Hα image of SN 1006 from the 4 m Blanco telescope at CTIO. Comparison with Chandra images from 2003 gives the first measurement of the X-ray proper motions around the entire periphery, carried out over a 9 yr baseline. We find that the expansion velocity varies significantly with azimuth. The highest velocity of ~7400 km s-1 (almost 2.5 times that in the northwest (NW)) is found along the southeast (SE) periphery, where both the kinematics and the spectra indicate that most of the X-ray emission stems from ejecta that have been decelerated little, if at all. Asymmetries in the distribution of ejecta are seen on a variety of spatial scales. Si-rich ejecta are especially prominent in the SE quadrant, while O and Mg are more uniformly distributed, indicating large-scale asymmetries arising from the explosion itself. Neon emission is strongest in a sharp filament just behind the primary shock along the NW rim, where the pre-shock density is highest. Here the Ne is likely interstellar, while Ne within the shell may include a contribution from ejecta. Within the interior of the projected shell we find a few isolated "bullets" of what appear to be supernova ejecta that are immediately preceded by bowshocks seen in Hα, features that we interpret as ejecta knots that have reached relatively dense regions of the surrounding interstellar medium, but that appear in the interior in projection. Recent three-dimensional hydrodynamic models for Type Ia supernovae display small-scale features that strongly resemble the ones seen in X-rays in SN 1006 an origin in the explosion itself or from subsequent hydrodynamic instabilities both remain viable options. We have expanded the search for precursor X-ray emission ahead of a synchrotron-dominated shock front, as expected from diffusive shock acceleration theory, to numerous regions along both the northeast

  4. Du Pont Classifications of 6 Supernovae

    NASA Astrophysics Data System (ADS)

    Morrell, N.; Shappee, Benjamin J.

    2016-06-01

    We report optical spectroscopy (range 370-910 nm) of six supernovae from the Backyard Observatory Supernova Search (BOSS) and the All-Sky Automated Survey for Supernovae (ASAS-SN) using the du Pont 2.5-m telescope (+ WFCCD) at Las Campanas Observatory on June 17 2016 UT. We performed a cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J.

  5. NASA Scientists Witness a Supernova Cosmic Rite of Passage

    NASA Astrophysics Data System (ADS)

    2005-11-01

    wind, comprising energetic ions, was shed by the progenitor star thousands to million of years before the explosion. If this were from the interstellar medium, it would be much denser than this stellar wind. NOAO Optical Image of SN 1970G NOAO Optical Image of SN 1970G Immler and Kuntz next studied the density profiles of all other supernovae that have been detected over the past two decades. Sure enough, the low-density circumstellar matter from the stellar wind was the source of X-rays, not the interstellar medium. Immler said that historical supernova remnants such as Cassiopeia A, which exploded some 320 years ago, also show no signs of activity from the interstellar medium. This is more than just a name game, more than hypothetically changing SN 1970G to SNR 1970G. "We have to rethink this notion that a shock wave from the supernova crashes into the interstellar medium to create a supernova remnant," said Immler. "The luminous supernova remnants that we see can be created without the need of a dense interstellar medium. In fact, our study showed that all supernovae detected in X-rays over the past 25 years live in a low-density environment." SN 1970G is located in the galaxy M101, also called the Pinwheel Galaxy, a stunning spiral galaxy about 22 million light years away in the constellation Ursa Major, home of the Big Dipper. Although the galaxy itself is visible from dark skies with binoculars, telescopes cannot resolve much structure in SN 1970G, unlike for supernova remnants in our Milky Way galaxy. Discovered with an optical telescope in 1970, SN 1970G was not seen with X-ray telescopes until the 1990s. Immler's work at NASA Goddard is supported through the Universities Space Research Association. Kuntz is supported through University of Maryland, Baltimore County. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for the Agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and

  6. Radio observations reveal a smooth circumstellar environment around the extraordinary type Ib supernova 2012au

    SciTech Connect

    Kamble, Atish; Soderberg, Alicia M.; Margutti, Raffaella; Milisavljevic, Dan; Chakraborti, Sayan; Dittmann, Jason; Drout, Maria; Sanders, Nathan; Chomiuk, Laura; Medvedev, Mikhail; Chevalier, Roger; Chugai, Nikolai; Fransson, Claes; Nakar, Ehud

    2014-12-10

    We present extensive radio and X-ray observations of SN 2012au, an energetic, radio-luminous supernova of Type Ib that exhibits multi-wavelength properties bridging subsets of hydrogen-poor superluminous supernovae, hypernovae, and normal core-collapse supernovae. The observations closely follow models of synchrotron emission from a shock-heated circumburst medium that has a wind density profile (ρ∝r {sup –2}). We infer a sub-relativistic velocity for the shock wave v ≈ 0.2 c and a radius of r ≈ 1.4 × 10{sup 16}cm at 25 days after the estimated date of explosion. For a wind velocity of 1000 km s{sup –1}, we determine the mass-loss rate of the progenitor to be M-dot =3.6×10{sup −6} M{sub ⊙} yr{sup −1}, consistent with the estimates from X-ray observations. We estimate the total internal energy of the radio-emitting material to be E ≈ 10{sup 47} erg, which is intermediate to SN 1998bw and SN 2002ap. The evolution of the radio light curve of SN 2012au is in agreement with its interaction with a smoothly distributed circumburst medium and the absence of stellar shells ejected from previous outbursts out to r ≈ 10{sup 17} cm from the supernova site. We conclude that the bright radio emission from SN 2012au was not dissimilar from other core-collapse supernovae despite its extraordinary optical properties, and that the evolution of the SN 2012au progenitor star was relatively quiet, marked with a steady mass loss, during the final years preceding explosion.

  7. Radio Observations Reveal a Smooth Circumstellar Environment Around the Extraordinary Type Ib Supernova 2012au

    NASA Astrophysics Data System (ADS)

    Kamble, Atish; Soderberg, Alicia M.; Chomiuk, Laura; Margutti, Raffaella; Medvedev, Mikhail; Milisavljevic, Dan; Chakraborti, Sayan; Chevalier, Roger; Chugai, Nikolai; Dittmann, Jason; Drout, Maria; Fransson, Claes; Nakar, Ehud; Sanders, Nathan

    2014-12-01

    We present extensive radio and X-ray observations of SN 2012au, an energetic, radio-luminous supernova of Type Ib that exhibits multi-wavelength properties bridging subsets of hydrogen-poor superluminous supernovae, hypernovae, and normal core-collapse supernovae. The observations closely follow models of synchrotron emission from a shock-heated circumburst medium that has a wind density profile (ρvpropr -2). We infer a sub-relativistic velocity for the shock wave v ≈ 0.2 c and a radius of r ≈ 1.4 × 1016cm at 25 days after the estimated date of explosion. For a wind velocity of 1000 km s-1, we determine the mass-loss rate of the progenitor to be \\dot{M} = 3.6 × 10-6 M⊙ yr-1, consistent with the estimates from X-ray observations. We estimate the total internal energy of the radio-emitting material to be E ≈ 1047 erg, which is intermediate to SN 1998bw and SN 2002ap. The evolution of the radio light curve of SN 2012au is in agreement with its interaction with a smoothly distributed circumburst medium and the absence of stellar shells ejected from previous outbursts out to r ≈ 1017 cm from the supernova site. We conclude that the bright radio emission from SN 2012au was not dissimilar from other core-collapse supernovae despite its extraordinary optical properties, and that the evolution of the SN 2012au progenitor star was relatively quiet, marked with a steady mass loss, during the final years preceding explosion.

  8. Expanding Molecular Bubble Surrounding Tycho’s Supernova Remnant (SN 1572) Observed with the IRAM 30 m Telescope: Evidence for a Single-degenerate Progenitor

    NASA Astrophysics Data System (ADS)

    Zhou, Ping; Chen, Yang; Zhang, Zhi-Yu; Li, Xiang-Dong; Safi-Harb, Samar; Zhou, Xin; Zhang, Xiao

    2016-07-01

    Whether the progenitors of SNe Ia are single-degenerate or double-degenerate white dwarf (WD) systems is a highly debated topic. To address the origin of Tycho’s Type Ia supernova remnant (SNR), SN 1572, we have carried out a 12CO J = 2–1 mapping and a 3 mm line survey toward the remnant using the IRAM 30 m telescope. We show that Tycho is surrounded by a clumpy molecular bubble at a local standard of rest velocity of ˜ 61 {km} {{{s}}}-1, which expands at a speed of ˜ 4.5 {km} {{{s}}}-1 and has a mass of ˜ 220 {M}ȯ (at the distance of 2.5 kpc). Enhanced 12CO J = 2–1 line emission relative to 12CO J = 1–0 emission and possible line broadenings (in velocity range ‑64 to ‑60 km s‑1) are found at the northeastern boundary of the SNR, where the shell is deformed and decelerated. These features, combined with the morphological correspondence between the expanding molecular bubble and Tycho, suggest that the SNR is associated with the bubble at the velocity range ‑66 to ‑57 km s‑1. The most plausible origin for the expanding bubble is the fast outflow (with velocity of hundreds km s‑1) driven from the vicinity of a WD as it accreted matter from a nondegenerate companion star. The SNR has been expanding in the low-density wind-blown bubble, and the shock wave has just reached the molecular cavity wall. This is the first unambiguous detection of an expanding bubble driven by the progenitor of a Type Ia SNR, which constitutes evidence for a single-degenerate progenitor for this SN Ia.

  9. Expanding Molecular Bubble Surrounding Tycho’s Supernova Remnant (SN 1572) Observed with the IRAM 30 m Telescope: Evidence for a Single-degenerate Progenitor

    NASA Astrophysics Data System (ADS)

    Zhou, Ping; Chen, Yang; Zhang, Zhi-Yu; Li, Xiang-Dong; Safi-Harb, Samar; Zhou, Xin; Zhang, Xiao

    2016-07-01

    Whether the progenitors of SNe Ia are single-degenerate or double-degenerate white dwarf (WD) systems is a highly debated topic. To address the origin of Tycho’s Type Ia supernova remnant (SNR), SN 1572, we have carried out a 12CO J = 2–1 mapping and a 3 mm line survey toward the remnant using the IRAM 30 m telescope. We show that Tycho is surrounded by a clumpy molecular bubble at a local standard of rest velocity of ∼ 61 {km} {{{s}}}-1, which expands at a speed of ∼ 4.5 {km} {{{s}}}-1 and has a mass of ∼ 220 {M}ȯ (at the distance of 2.5 kpc). Enhanced 12CO J = 2–1 line emission relative to 12CO J = 1–0 emission and possible line broadenings (in velocity range ‑64 to ‑60 km s‑1) are found at the northeastern boundary of the SNR, where the shell is deformed and decelerated. These features, combined with the morphological correspondence between the expanding molecular bubble and Tycho, suggest that the SNR is associated with the bubble at the velocity range ‑66 to ‑57 km s‑1. The most plausible origin for the expanding bubble is the fast outflow (with velocity of hundreds km s‑1) driven from the vicinity of a WD as it accreted matter from a nondegenerate companion star. The SNR has been expanding in the low-density wind-blown bubble, and the shock wave has just reached the molecular cavity wall. This is the first unambiguous detection of an expanding bubble driven by the progenitor of a Type Ia SNR, which constitutes evidence for a single-degenerate progenitor for this SN Ia.

  10. The Origin of Kepler's Supernova Remnant

    NASA Astrophysics Data System (ADS)

    Patnaude, Daniel J.; Badenes, Carles; Park, Sangwook; Laming, J. Martin

    2012-09-01

    It is now well established that Kepler's supernova remnant (SNR) is the result of a Type Ia explosion. With an age of 407 yr and an angular diameter of ~4', Kepler is estimated to be between 3.0 and 7.0 kpc distant. Unlike other Galactic Type Ia SNRs such as Tycho and SN 1006, and SNR 0509-67.5 in the Large Magellanic Cloud, Kepler shows evidence for a strong circumstellar interaction. A bowshock structure in the north is thought to originate from the motion of a mass-losing system through the interstellar medium prior to the supernova. We present results of hydrodynamical and spectral modeling aimed at constraining the circumstellar environment of the system and the amount of 56Ni produced in the explosion. Using models that contain either 0.3 M ⊙ (subenergetic) or 1.0 M ⊙ (energetic) of 56Ni, we simulate the interaction between supernova Ia ejecta and various circumstellar density models. Based on dynamical considerations alone, we find that the subenergetic models favor a distance to the SNR of <6.4 kpc, while the model that produces 1 M ⊙ of 56Ni requires a distance to the SNR of >7 kpc. The X-ray spectrum is consistent with an explosion that produced ~1 M ⊙ of 56Ni, ruling out the subenergetic models, and suggesting that Kepler's SNR was an SN 1991T-like event. Additionally, the X-ray spectrum rules out a pure r -2 wind profile expected from isotropic mass loss up to the time of the supernova. Introducing a small cavity around the progenitor system results in modeled X-ray spectra that are consistent with the observed spectrum. If a wind-shaped circumstellar environment is necessary to explain the dynamics and X-ray emission from the shocked ejecta in Kepler's SNR, then we require that the distance to the remnant be greater than 7 kpc.

  11. DISENTANGLING THE ORIGIN AND HEATING MECHANISM OF SUPERNOVA DUST: LATE-TIME SPITZER SPECTROSCOPY OF THE TYPE IIn SN 2005ip

    SciTech Connect

    Fox, Ori D.; Chevalier, Roger A.; Skrutskie, Michael F.; Leisenring, Jarron M.; Dwek, Eli; Sugerman, Ben E. K.

    2010-12-20

    This paper presents late-time near-infrared and Spitzer mid-infrared photometric and spectroscopic observations of warm dust in the Type IIn SN 2005ip in NGC 2906. The spectra show evidence for two dust components with different temperatures. Spanning the peak of the thermal emission, these observations provide strong constraints on the dust mass, temperature, and luminosity, which serve as critical diagnostics for disentangling the origin and heating mechanism of each component. The results suggest that the warmer dust has a mass of {approx}5 x 10{sup -4} M{sub sun}, originates from newly formed dust in the ejecta, or possibly the cool, dense shell, and is continuously heated by the circumstellar interaction. By contrast, the cooler component likely originates from a circumstellar shock echo that forms from the heating of a large, pre-existing dust shell {approx}0.01-0.05 M{sub sun} by the late-time circumstellar interaction. The progenitor wind velocity derived from the blue edge of the He I 1.083 {mu}m P Cygni profile indicates a progenitor eruption likely formed this dust shell {approx}100 years prior to the supernova explosion, which is consistent with a Luminous Blue Variable progenitor star.

  12. Disentangling the Origin and Heating Mechanism of Supernova Dust: Late-Time Spitzer Spectroscopy of the Type IIn SN 2005ip

    NASA Technical Reports Server (NTRS)

    Fox, Ori D.; Chevalier, Roger A.; Dwek, Eli; Skrutskie, Michael F.; Sugerman, Ben E. K.; Leisenring, Jarron M.

    2010-01-01

    This paper presents late-time near-infrared and Spitzer mid-infrared photometric and spectroscopic observations of warm dust in the Type IIn SN 2005ip in NGC 2906. The spectra show evidence for two dust components with different temperatures. Spanning the peak of the thermal emission, these observations provide strong constraints on the dust mass, temperature, and luminosity, which serve as critical diagnostics for disentangling the origin and heating mechanism of each component. The results suggest the warmer dust has a mass of approx. 5 x 10(exp -4) Solar Mass and originates from newly formed dust in the ejecta, continuously heated by the circumstellar interaction. By contrast, the cooler component likely originates from a circumstellar shock echo that forms from the heating of a large, pre-existing dust shell approx. 0.01 - 0.05 Solar Mass by the late-time circumstellar interaction. The progenitor wind velocity derived from the blue edge of the He I 1.083 micro P Cygni profile indicates a progenitor eruption likely formed this dust shell approx.100 years prior to the supernova explosion, which is consistent with a Luminous Blue Variable (LBV) progenitor star. Subject

  13. SN 2005ip: A luminous type IIn supernova emerging from a dense circumstellar medium as revealed by X-ray observations

    SciTech Connect

    Katsuda, Satoru; Maeda, Keiichi; Nozawa, Takaya; Pooley, David; Immler, Stefan

    2014-01-10

    We report on the X-ray spectral evolution of the nearby Type IIn supernova (SN) 2005ip based on Chandra and Swift observations covering ∼1-6 yr after explosion. X-ray spectra in all epochs are well fitted by a thermal emission model with kT ≳ 7 keV. The somewhat high temperature suggests that the X-ray emission mainly arises from the circumstellar medium (CSM) heated by the forward shock. We find that the spectra taken two to three years after the explosion are heavily absorbed (N {sub H} ∼ 5 × 10{sup 22} cm{sup –2}), but the absorption gradually decreases to the level of the Galactic absorption (N {sub H} ∼ 4 × 10{sup 20} cm{sup –2}) at the final epoch. This indicates that the SN went off in a dense CSM and that the forward shock has overtaken it. The intrinsic X-ray luminosity stays constant until the final epoch, when it drops by a factor of ∼2. The intrinsic 0.2-10 keV luminosity during the plateau phase is measured to be ∼1.5 × 10{sup 41} erg s{sup –1}, ranking SN 2005ip as one of the brightest X-ray SNe. Based on the column density, we derive a lower limit of a mass-loss rate to be M-dot ∼1.5×10{sup −2} (V{sub w} /100 km s{sup –1}) M {sub ☉} yr{sup –1}, which roughly agrees with that inferred from the X-ray luminosity, M-dot ∼2×10{sup −2} (V{sub w} /100 km s{sup –1}) M {sub ☉} yr{sup –1}, where V{sub w} is the circumstellar wind speed. Such a high mass-loss rate suggests that the progenitor star had eruptive mass ejections similar to a luminous blue variable star. The total mass ejected in the eruptive period is estimated to be ∼15 M {sub ☉}, indicating that the progenitor mass is ≳ 25 M {sub ☉}.

  14. Dust Production and Particle Acceleration in Supernova 1987A Revealed with ALMA

    NASA Astrophysics Data System (ADS)

    Indebetouw, R.; Matsuura, M.; Dwek, E.; Zanardo, G.; Barlow, M. J.; Baes, M.; Bouchet, P.; Burrows, D. N.; Chevalier, R.; Clayton, G. C.; Fransson, C.; Gaensler, B.; Kirshner, R.; Lakićević, M.; Long, K. S.; Lundqvist, P.; Martí-Vidal, I.; Marcaide, J.; McCray, R.; Meixner, M.; Ng, C.-Y.; Park, S.; Sonneborn, G.; Staveley-Smith, L.; Vlahakis, C.; van Loon, J.

    2014-02-01

    Supernova (SN) explosions are crucial engines driving the evolution of galaxies by shock heating gas, increasing the metallicity, creating dust, and accelerating energetic particles. In 2012 we used the Atacama Large Millimeter/Submillimeter Array to observe SN 1987A, one of the best-observed supernovae since the invention of the telescope. We present spatially resolved images at 450 μm, 870 μm, 1.4 mm, and 2.8 mm, an important transition wavelength range. Longer wavelength emission is dominated by synchrotron radiation from shock-accelerated particles, shorter wavelengths by emission from the largest mass of dust measured in a supernova remnant (>0.2 M ⊙). For the first time we show unambiguously that this dust has formed in the inner ejecta (the cold remnants of the exploded star's core). The dust emission is concentrated at the center of the remnant, so the dust has not yet been affected by the shocks. If a significant fraction survives, and if SN 1987A is typical, supernovae are important cosmological dust producers.

  15. DUST PRODUCTION AND PARTICLE ACCELERATION IN SUPERNOVA 1987A REVEALED WITH ALMA

    SciTech Connect

    Indebetouw, R.; Chevalier, R.; Matsuura, M.; Barlow, M. J.; Dwek, E.; Zanardo, G.; Baes, M.; Bouchet, P.; Burrows, D. N.; Clayton, G. C.; Fransson, C.; Lundqvist, P.; Gaensler, B.; Kirshner, R.; Lakićević, M.; Long, K. S.; Meixner, M.; Martí-Vidal, I.; Marcaide, J.; and others

    2014-02-10

    Supernova (SN) explosions are crucial engines driving the evolution of galaxies by shock heating gas, increasing the metallicity, creating dust, and accelerating energetic particles. In 2012 we used the Atacama Large Millimeter/Submillimeter Array to observe SN 1987A, one of the best-observed supernovae since the invention of the telescope. We present spatially resolved images at 450 μm, 870 μm, 1.4 mm, and 2.8 mm, an important transition wavelength range. Longer wavelength emission is dominated by synchrotron radiation from shock-accelerated particles, shorter wavelengths by emission from the largest mass of dust measured in a supernova remnant (>0.2 M {sub ☉}). For the first time we show unambiguously that this dust has formed in the inner ejecta (the cold remnants of the exploded star's core). The dust emission is concentrated at the center of the remnant, so the dust has not yet been affected by the shocks. If a significant fraction survives, and if SN 1987A is typical, supernovae are important cosmological dust producers.

  16. Dust Production and Particle Acceleration in Supernova 1987A Revealed with ALMA

    NASA Technical Reports Server (NTRS)

    Indebetouw, R.; Matsuura, M.; Dwek, E.; Zanardo, G.; Barlow, M. J.; Baes, M.; Bouchet, P.; Burrows, D. N.; Chevalier, R.; Clayton, G. C.; Fransson, C.; Gaensler, B.; Kirshner, R.; Lakicevic, M.; Long, K. S.; Lundqvist, P.; Marti-Vidal, I.; Marcaide, J.; McCray, R.; Meixner, M.; Ng, C.-Y.; Park, S.; Sonneborn, G.; Staveley-Smith, L.; vanLoon, J.

    2014-01-01

    Supernova (SN) explosions are crucial engines driving the evolution of galaxies by shock heating gas, increasing the metallicity, creating dust, and accelerating energetic particles. In 2012 we used the Atacama Large Millimeter/ Submillimeter Array to observe SN1987A, one of the best-observed supernovae since the invention of the telescope. We present spatially resolved images at 450 µm, 870 µm, 1.4 mm, and 2.8 mm, an important transition wavelength range. Longer wavelength emission is dominated by synchrotron radiation from shock-accelerated particles, shorter wavelengths by emission from the largest mass of dust measured in a supernova remnant (>0.2 Solar Mass). For the first time we show unambiguously that this dust has formed in the inner ejecta (the cold remnants of the exploded star's core). The dust emission is concentrated at the center of the remnant, so the dust has not yet been affected by the shocks. If a significant fraction survives, and if SN 1987A is typical, supernovae are important cosmological dust producers.

  17. X-Ray Synchrotron Emission From 10-100 TeV Cosmic-Ray Electrons In The Supernova Remnant SN 1006

    NASA Technical Reports Server (NTRS)

    Allen, G. E.; Petre, R.; Gotthelf, E. V.

    2001-01-01

    We present the results of a joint spectral analysis of RXTE PCA, ASCA SIS, and ROSAT PSPC data of the supernova remnant SN 1006. This work represents the first attempt to model both the thermal and nonthermal X-ray emission over the entire X-ray energy band from 0.12 to 17 key. The thermal flux is described by a nonequilibrium ionization model with an electron temperature kTe = 0.6 key, an ionization timescale n(sub 0)t = 9 x 10(exp 9)/cc s, and a relative elemental abundance of silicon that is 10 - 18 times larger than the solar abundance. The nonthermal X-ray spectrum is described by a broken power law model with low- and high-energy photon indices Gamma(sub 1) = 2.1 and Gamma(sub 2) = 3.0, respectively. Since the nonthermal X-ray spectrum steepens with increasing energy, the results of the present analysis corroborate previous claims that the nonthermal X-ray emission is produced by synchrotron radiation. We argue that the magnetic field strength is significantly larger than previous estimates of about 10 micro G and arbitrarily use a value of 40 micro G to estimate the parameters of the cosmic-ray electron, proton, and helium spectra of the remnant. The results for the ratio of the number densities of protons and electrons (R = 160 at 1 GeV), the total energy in cosmic rays (E(sub cr) = 1 x 10(exp 50) ergs), and the spectral index of the electrons at 1 GeV (Gamma(sub e) = 2.14 +/- 0.12) are consistent with the hypothesis that Galactic cosmic rays are accelerated predominantly in the shocks of supernova remnants. Yet, the remnant may or may not accelerate nuclei to energies as high as the energy of the "knee," depending on the reason why the maximum energy of the electrons is only 10 TeV.

  18. NASA's Chandra Sees Brightest Supernova Ever

    NASA Astrophysics Data System (ADS)

    2007-05-01

    WASHINGTON - The brightest stellar explosion ever recorded may be a long-sought new type of supernova, according to observations by NASA's Chandra X-ray Observatory and ground-based optical telescopes. This discovery indicates that violent explosions of extremely massive stars were relatively common in the early universe, and that a similar explosion may be ready to go off in our own galaxy. "This was a truly monstrous explosion, a hundred times more energetic than a typical supernova," said Nathan Smith of the University of California at Berkeley, who led a team of astronomers from California and the University of Texas in Austin. "That means the star that exploded might have been as massive as a star can get, about 150 times that of our sun. We've never seen that before." Chandra X-ray Image of SN 2006gy Chandra X-ray Image of SN 2006gy Astronomers think many of the first generation of stars were this massive, and this new supernova may thus provide a rare glimpse of how the first stars died. It is unprecedented, however, to find such a massive star and witness its death. The discovery of the supernova, known as SN 2006gy, provides evidence that the death of such massive stars is fundamentally different from theoretical predictions. "Of all exploding stars ever observed, this was the king," said Alex Filippenko, leader of the ground-based observations at the Lick Observatory at Mt. Hamilton, Calif., and the Keck Observatory in Mauna Kea, Hawaii. "We were astonished to see how bright it got, and how long it lasted." The Chandra observation allowed the team to rule out the most likely alternative explanation for the supernova: that a white dwarf star with a mass only slightly higher than the sun exploded into a dense, hydrogen-rich environment. In that event, SN 2006gy should have been 1,000 times brighter in X-rays than what Chandra detected. Animation of SN 2006gy Animation of SN 2006gy "This provides strong evidence that SN 2006gy was, in fact, the death of an

  19. SN 1604 in China

    NASA Astrophysics Data System (ADS)

    Wang, Z. R.; Zhao, Y.; Li, M.; Zhou, Q. L.

    2005-06-01

    The 6th East Asian Meeting of Astronomy was held just at the time of 400 years after the discovery of SN (supernova) 1604 and its pre-maximum observation by the astronomers both from the East and the West in the 17th century. It has a special meaning and is interesting to look back on the historical observation of SN 1604. In this paper, we only limit to concern the Chinese observation on SN 1604.

  20. Supernova Ejecta in the Youngest Galactic Supernova Remnant G1.9+0.3

    NASA Technical Reports Server (NTRS)

    Borkowski, Kazimierz J.; Reynolds, Stephen P.; Hwang, Una; Green, David A.; Petre, Robert; Krishnamurthy, Kalyani; Willett, Rebecca

    2013-01-01

    G1.9+0.3 is the youngest known Galactic supernova remnant (SNR), with an estimated supernova (SN) explosion date of approximately 1900, and most likely located near the Galactic Center. Only the outermost ejecta layers with free-expansion velocities (is) approximately greater than 18,000 km s-1 have been shocked so far in this dynamically young, likely Type Ia SNR. A long (980 ks) Chandra observation in 2011 allowed spatially-resolved spectroscopy of heavy-element ejecta. We denoised Chandra data with the spatio-spectral method of Krishnamurthy et al., and used a wavelet based technique to spatially localize thermal emission produced by intermediate-mass elements (IMEs: Si and S) and iron. The spatial distribution of both IMEs and Fe is extremely asymmetric, with the strongest ejecta emission in the northern rim. Fe K alpha emission is particularly prominent there, and fits with thermal models indicate strongly oversolar Fe abundances. In a localized, outlying region in the northern rim, IMEs are less abundant than Fe, indicating that undiluted Fe-group elements (including 56Ni) with velocities greater than 18,000 km s-1 were ejected by this SN. But in the inner west rim, we find Si- and S-rich ejecta without any traces of Fe, so high-velocity products of O-burning were also ejected. G1.9+0.3 appears similar to energetic Type Ia SNe such as SN 2010jn where iron-group elements at such high free-expansion velocities have been recently detected. The pronounced asymmetry in the ejecta distribution and abundance inhomogeneities are best explained by a strongly asymmetric SN explosion, similar to those produced in some recent 3D delayed-detonation Type Ia models.

  1. SUPERNOVA EJECTA IN THE YOUNGEST GALACTIC SUPERNOVA REMNANT G1.9+0.3

    SciTech Connect

    Borkowski, Kazimierz J.; Reynolds, Stephen P.; Hwang, Una; Green, David A.; Petre, Robert

    2013-07-01

    G1.9+0.3 is the youngest known Galactic supernova remnant (SNR), with an estimated supernova (SN) explosion date of {approx}1900, and most likely located near the Galactic center. Only the outermost ejecta layers with free-expansion velocities {approx}>18,000 km s{sup -1} have been shocked so far in this dynamically young, likely Type Ia SNR. A long (980 ks) Chandra observation in 2011 allowed spatially resolved spectroscopy of heavy-element ejecta. We denoised Chandra data with the spatio-spectral method of Krishnamurthy et al., and used a wavelet-based technique to spatially localize thermal emission produced by intermediate-mass elements (IMEs; Si and S) and iron. The spatial distribution of both IMEs and Fe is extremely asymmetric, with the strongest ejecta emission in the northern rim. Fe K{alpha} emission is particularly prominent there, and fits with thermal models indicate strongly oversolar Fe abundances. In a localized, outlying region in the northern rim, IMEs are less abundant than Fe, indicating that undiluted Fe-group elements (including {sup 56}Ni) with velocities >18,000 km s{sup -1} were ejected by this SN. However, in the inner west rim, we find Si- and S-rich ejecta without any traces of Fe, so high-velocity products of O-burning were also ejected. G1.9+0.3 appears similar to energetic Type Ia SNe such as SN 2010jn where iron-group elements at such high free-expansion velocities have been recently detected. The pronounced asymmetry in the ejecta distribution and abundance inhomogeneities are best explained by a strongly asymmetric SN explosion, similar to those produced in some recent three-dimensional delayed-detonation Type Ia models.

  2. Pair instability supernovae of very massive population III stars

    SciTech Connect

    Chen, Ke-Jung; Woosley, Stan; Heger, Alexander; Almgren, Ann; Whalen, Daniel J.

    2014-09-01

    Numerical studies of primordial star formation suggest that the first stars in the universe may have been very massive. Stellar models indicate that non-rotating Population III stars with initial masses of 140-260 M {sub ☉} die as highly energetic pair-instability supernovae. We present new two-dimensional simulations of primordial pair-instability supernovae done with the CASTRO code. Our simulations begin at earlier times than previous multidimensional models, at the onset of core contraction, to capture any dynamical instabilities that may be seeded by core contraction and explosive burning. Such instabilities could enhance explosive yields by mixing hot ash with fuel, thereby accelerating nuclear burning, and affect the spectra of the supernova by dredging up heavy elements from greater depths in the star at early times. Our grid of models includes both blue supergiants and red supergiants over the range in progenitor mass expected for these events. We find that fluid instabilities driven by oxygen and helium burning arise at the upper and lower boundaries of the oxygen shell ∼20-100 s after core bounce. Instabilities driven by burning freeze out after the SN shock exits the helium core. As the shock later propagates through the hydrogen envelope, a strong reverse shock forms that drives the growth of Rayleigh-Taylor instabilities. In red supergiant progenitors, the amplitudes of these instabilities are sufficient to mix the supernova ejecta.

  3. Gamma-Ray Burst Associated Supernovae: Outliers Become Mainstream

    NASA Technical Reports Server (NTRS)

    Pian, E.; Mazzali, P.; Masetti, N.; Ferrero, P.; Klose, S.; Palazzi, E.; Ramirez-Ruiz, E.; Woosley, S. E.; Kouveliotou, C.; Deng, J.

    2006-01-01

    During the last eight years a clear connection has been established-between the two most powerful explosions in our Universe: core-collapse supernovae (SNe) and long gamma ray bursts (GRBs). Theory suggests4 that every GRB is simultaneously accompanied by a SN, but in only a few nearby cases have these two phenomena been observed together. We report the discovery and daily monitoring of SN 2006aj associated with the GRB 060218. Because the event was the second closest GRB, both explosions could be examined in detail. GRB 060218 had an unusually soft spectrum, long duration, and a total energy 100 to 1000 times less than most other GRBs. Yet SN 2006aj was similar to those in other GRBs, aside from rising more rapidly and being approximately 40% fainter. Taken together, these observations suggest that GRBs have two components: a broad, energetic, but only mildly relativistic outflow that makes a SN, and a more narrowly focused, highly relativistic jet responsible for the GRB. The properties of the GRB jet apparently vary greatly from event to event, while the broad SN outflow varies much less. Low energy transients like GRB 060218 may be the most common events in the Universe.

  4. Supernova 2007bi as a pair-instability explosion.

    PubMed

    Gal-Yam, A; Mazzali, P; Ofek, E O; Nugent, P E; Kulkarni, S R; Kasliwal, M M; Quimby, R M; Filippenko, A V; Cenko, S B; Chornock, R; Waldman, R; Kasen, D; Sullivan, M; Beshore, E C; Drake, A J; Thomas, R C; Bloom, J S; Poznanski, D; Miller, A A; Foley, R J; Silverman, J M; Arcavi, I; Ellis, R S; Deng, J

    2009-12-01

    Stars with initial masses such that 10M[symbol: see text] supernova. By contrast, extremely massive stars with M(initial) >or= 140M[symbol: see text] (if such exist) develop oxygen cores with masses, M(core), that exceed 50M[symbol: see text], where high temperatures are reached at relatively low densities. Conversion of energetic, pressure-supporting photons into electron-positron pairs occurs before oxygen ignition and leads to a violent contraction which triggers a nuclear explosion that unbinds the star in a pair-instability supernova. Transitional objects with 100M[symbol: see text] < M(initial) < 140M[symbol: see text] may end up as iron-core-collapse supernovae following violent mass ejections, perhaps as a result of brief episodes of pair instability, and may already have been identified. Here we report observations of supernova SN 2007bi, a luminous, slowly evolving object located within a dwarf galaxy. We estimate the exploding core mass to be M(core) approximately 100M[symbol: see text], in which case theory unambiguously predicts a pair-instability supernova. We show that >3M[symbol: see text] of radioactive (56)Ni was synthesized during the explosion and that our observations are well fitted by models of pair-instability supernovae. This indicates that nearby dwarf galaxies probably host extremely massive stars, above the apparent Galactic stellar mass limit, which perhaps result from processes similar to those that created the first stars in the Universe. PMID:19956255

  5. SN 2008D: A WOLF-RAYET EXPLOSION THROUGH A THICK WIND

    SciTech Connect

    Svirski, Gilad; Nakar, Ehud

    2014-06-10

    Supernova (SN) 2008D/XRT 080109 is considered to be the only direct detection of a shock breakout from a regular SN to date. While a breakout interpretation was favored by several papers, inconsistencies remain between the observations and current SN shock breakout theory. Most notably, the duration of the luminous X-ray pulse is considerably longer than expected for a spherical breakout through the surface of a type Ibc SN progenitor, and the X-ray radiation features, mainly its flat spectrum and its luminosity evolution, are enigmatic. We apply a recently developed theoretical model for the observed radiation from a Wolf-Rayet SN exploding through a thick wind and show that it naturally explains all of the observed features of SN 2008D X-ray emission, including the energetics, the spectrum, and the detailed luminosity evolution. We find that the inferred progenitor and SN parameters are typical for an exploding Wolf-Rayet. A comparison of the wind density found at the breakout radius and the density at much larger radii, as inferred by late radio observations, suggests an enhanced mass-loss rate taking effect about 10 days prior to the SN explosion. This finding joins accumulating evidence for a possible late phase in the stellar evolution of massive stars, involving vigorous mass loss a short time before the SN explosion.

  6. SN 2008D: A Wolf-Rayet Explosion Through a Thick Wind

    NASA Astrophysics Data System (ADS)

    Svirski, Gilad; Nakar, Ehud

    2014-06-01

    Supernova (SN) 2008D/XRT 080109 is considered to be the only direct detection of a shock breakout from a regular SN to date. While a breakout interpretation was favored by several papers, inconsistencies remain between the observations and current SN shock breakout theory. Most notably, the duration of the luminous X-ray pulse is considerably longer than expected for a spherical breakout through the surface of a type Ibc SN progenitor, and the X-ray radiation features, mainly its flat spectrum and its luminosity evolution, are enigmatic. We apply a recently developed theoretical model for the observed radiation from a Wolf-Rayet SN exploding through a thick wind and show that it naturally explains all of the observed features of SN 2008D X-ray emission, including the energetics, the spectrum, and the detailed luminosity evolution. We find that the inferred progenitor and SN parameters are typical for an exploding Wolf-Rayet. A comparison of the wind density found at the breakout radius and the density at much larger radii, as inferred by late radio observations, suggests an enhanced mass-loss rate taking effect about 10 days prior to the SN explosion. This finding joins accumulating evidence for a possible late phase in the stellar evolution of massive stars, involving vigorous mass loss a short time before the SN explosion.

  7. Interacting supernovae and supernova impostors: Evidence of incoming supernova explosions?

    SciTech Connect

    Tartaglia, L.

    2015-02-24

    Violent eruptions, and consequently major mass loss, are a common feature of the so–called Luminous Blue Variable (LBV) stars. During major eruptive episodes LBVs mimic the behavior of real type IIn supernovae (SNe), showing comparable radiated energy and similar spectroscopic properties. For this reason these events are frequently labelled as SN impostors. Type IIn SN spectra are characterized by the presence of prominent narrow Balmer lines in emission. In most cases, SNe IIn arise from massive stars (M>8{sub ⊙}) exploding in a dense H–rich circumstellar medium (CSM), produced by progenitor’s mass loss prior to the SN explosion. Although the mechanisms triggering these eruptions are still unknown, recently we had direct proofs of the connection between very massive stars, their eruptions and ejecta-CSM interacting SNe. SNe 2006jc, 2010mc, 2011ht and the controversial SN 2009ip are famous cases in which we observed the explosion of the star months to years after major outbursts. In this context, the case of a recent transient event, LSQ13zm, is extremely interesting since we observed an outburst just ∼3 weeks before the terminal SN explosion. All of this may suggest that SN impostors occasionally herald true SN explosions. Nonetheless, there are several cases where major eruptions are followed by a quiescent phase in the LBV life. The impostor SN 2007sv is one of these cases, since it showed a single outburst event. Its photometric (a relatively faint absolute magnitude at the maximum) and spectroscopic properties (low velocity and temperature of the ejecta, and the absence of the typical elements produced in the explosive nucleosynthesis) strongly suggest that SN 2007sv was the giant eruption of an LBV, which has then returned in a quiescent stage.

  8. Interacting supernovae and supernova impostors: Evidence of incoming supernova explosions?

    NASA Astrophysics Data System (ADS)

    Tartaglia, L.

    2015-02-01

    Violent eruptions, and consequently major mass loss, are a common feature of the so-called Luminous Blue Variable (LBV) stars. During major eruptive episodes LBVs mimic the behavior of real type IIn supernovae (SNe), showing comparable radiated energy and similar spectroscopic properties. For this reason these events are frequently labelled as SN impostors. Type IIn SN spectra are characterized by the presence of prominent narrow Balmer lines in emission. In most cases, SNe IIn arise from massive stars (M>8⊙) exploding in a dense H-rich circumstellar medium (CSM), produced by progenitor's mass loss prior to the SN explosion. Although the mechanisms triggering these eruptions are still unknown, recently we had direct proofs of the connection between very massive stars, their eruptions and ejecta-CSM interacting SNe. SNe 2006jc, 2010mc, 2011ht and the controversial SN 2009ip are famous cases in which we observed the explosion of the star months to years after major outbursts. In this context, the case of a recent transient event, LSQ13zm, is extremely interesting since we observed an outburst just ˜3 weeks before the terminal SN explosion. All of this may suggest that SN impostors occasionally herald true SN explosions. Nonetheless, there are several cases where major eruptions are followed by a quiescent phase in the LBV life. The impostor SN 2007sv is one of these cases, since it showed a single outburst event. Its photometric (a relatively faint absolute magnitude at the maximum) and spectroscopic properties (low velocity and temperature of the ejecta, and the absence of the typical elements produced in the explosive nucleosynthesis) strongly suggest that SN 2007sv was the giant eruption of an LBV, which has then returned in a quiescent stage.

  9. A Novel Multigrid Method for Sn Discretizations of the Mono-Energetic Boltzmann Transport Equation in the Optically Thick and Thin Regimes with Anisotropic Scattering, Part I

    SciTech Connect

    Lee, Barry

    2010-05-01

    This paper presents a new multigrid method applied to the most common Sn discretizations (Petrov-Galerkin, diamond-differenced, corner-balanced, and discontinuous Galerkin) of the mono-energetic Boltzmann transport equation in the optically thick and thin regimes, and with strong anisotropic scattering. Unlike methods that use scalar DSA diffusion preconditioners for the source iteration, this multigrid method is applied directly to an integral equation for the scalar flux. Thus, unlike the former methods that apply a multigrid strategy to the scalar DSA diffusion operator, this method applies a multigrid strategy to the integral source iteration operator, which is an operator for 5 independent variables in spatial 3-d (3 in space and 2 in angle) and 4 independent variables in spatial 2-d (2 in space and 2 in angle). The core smoother of this multigrid method involves applications of the integral operator. Since the kernel of this integral operator involves the transport sweeps, applying this integral operator requires a transport sweep (an inversion of an upper triagular matrix) for each of the angles used. As the equation is in 5-space or 4-space, the multigrid approach in this paper coarsens in both angle and space, effecting efficient applications of the coarse integral operators. Although each V-cycle of this method is more expensive than a V-cycle for the DSA preconditioner, since the DSA equation does not have angular dependence, the overall computational efficiency is about the same for problems where DSA preconditioning {\\it is} effective. This new method also appears to be more robust over all parameter regimes than DSA approaches. Moreover, this new method is applicable to a variety of Sn spatial discretizations, to problems involving a combination of optically thick and thin regimes, and more importantly, to problems with anisotropic scattering cross-sections, all of which DSA approaches perform poorly or not applicable at all. This multigrid approach

  10. Supernova 1987A

    NASA Technical Reports Server (NTRS)

    Mccray, Richard; Li, Hong Wei

    1988-01-01

    Supernova 1987A (February 23, 1987) in the Large Magellanic Cloud is the brightest supernova to be observed since SN 1604 AD (Kepler). Detection of a burst of neutrinos indicates that a neutron star was formed. Radioactive decay of about 0.07 solar mass of Co-56 is responsible for the observed optical light as well as hard X-rays and gamma-ray lines. Ultraviolet, optical, and infrared 'light echoes' and soft X-rays provide information on the distribution of circumstellar matter and the evolution of the progenitor star.

  11. Light-echo spectroscopy of historic Supernovae

    NASA Astrophysics Data System (ADS)

    Krause, Oliver

    Young Galactic supernova remnants are unique laboratories for supernova physics. Due to their proximity they provide us with the most detailed view of the outcome of a supernova. However, the exact spectroscopic types of their original explosions have been undetermined so far -hindering to link the wealth of multi-wavelength knowledge about their remnants with the diverse population of supernovae. Light echoes, reflektions of the brilliant supernova burst of light by interstellar dust, provide a unique opportunity to reobserve today -with powerful scientific instruments of the 21st century -historic supernova exlosions even after hundreds of years and to conclude on their nature. We report on optical light-echo spectroscopy of two famous Galactic supernovae: Tycho Brahe's SN 1572 and the supernova that created the Cassiopeia A remnant around the year 1680. These observations finally recovered the missing spectroscopic classifications and provide new constraints on explosion models for future studies.

  12. Observing Supernovae and Supernova Remnants with JWST

    NASA Astrophysics Data System (ADS)

    Sonneborn, George; Temim, Tea; Williams, Brian J.; Blair, William P.

    2015-01-01

    The James Webb Space Telescope (JWST) will enable near- and mid-infrared studies of supernovae (SN) and supernova remnants (SNR) in the Milky Way and galaxies throughout the local universe and to high redshift. JWST's instrumentation provides imaging, coronography, and spectroscopy (R<3000) over the wavelength range 1-29 microns. The unprecedented sensitivity and angular resolution will enable spectroscopic study of new and recent supernovae, including molecule and dust formation, in galaxies at least out to 30 Mpc, and imaging to much greater distances. The Target of Opportunity response time can be as short as 48 hours, enabling quick follow-up observations of important SN events. JWST will be ideal for the study of Galactic and Magellanic Clouds supernova remnants, particularly young remnants with hot dust. Its high angular resolution (0.07" at 2 microns, 0.7" at 20 microns) will allow direct comparison between the IR, optical, and X-ray morphologies, identifying sites of dust emission in both the ejecta and the shocked ISM unresolved by previous IR telescopes. There is a rich spectrum of atomic lines (H, He I, [Si I], [Fe II], [Ni I-III], [Co II-III], [S III-IV], [Ar II-III], [Ne II, III, V], [O IV]) and molecules (CO, SiO, H2) of importance for SN and SNR studies. JWST is a large aperture (6.5m), cryogenic, infrared-optimized space observatory under construction by NASA, ESA, and CSA for launch in 2018. The JWST observatory will be placed in an Earth-Sun L2 orbit by an Ariane 5 launch vehicle provided by ESA. The observatory is designed for a 5-year prime science mission, with consumables for 10 years of science operations. The first call for proposals for JWST observations will be released in 2017.

  13. Supernovae, young remnants, and nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Kirshner, R. P.

    1982-01-01

    Chemical abundance data from extragalactic supernovae and from supernova remnants (SNR) less than 1000 yrs old are employed to show that nuclear burning beyond helium synthesis actually occurs. Supernova (SN) are classified into types I or II, having no hydrogen lines or featuring hydrogen lines, respectively. The SN I's have been observed as having a preponderance of Fe lines, and emitting from a source at around 12,000 K with a center continuum of approximately 10 AU. Decay chains which could account for detected luminosities and spectra are presented, noting a good fit of Fe II spectrum with observed SN spectra. SNR pass through younger and older stages, going from the outpouring of material to diffusion in the interstellar medium. Expanding flocculi from young SNR show oxygen abundances as well as lines from sulfur, calcium, and argon, with a corresponding necessity of an explosive source of 15 solar masses.

  14. Spectra ID of recent SN

    NASA Astrophysics Data System (ADS)

    Challis, Peter

    2013-12-01

    P. Challis, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf of the CfA Supernova Group, report spectra (range 320-860 nm) of various SN obtained during Dec. 24-27 UT by P. Challis, S. Gottilla (MMTO.org), and E. Marin (MMTO.org) with the MMT 6.5-m telescope (+ Blue Channel). Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J.

  15. FUZZY SUPERNOVA TEMPLATES. I. CLASSIFICATION

    SciTech Connect

    Rodney, Steven A.; Tonry, John L. E-mail: jt@ifa.hawaii.ed

    2009-12-20

    Modern supernova (SN) surveys are now uncovering stellar explosions at rates that far surpass what the world's spectroscopic resources can handle. In order to make full use of these SN data sets, it is necessary to use analysis methods that depend only on the survey photometry. This paper presents two methods for utilizing a set of SN light-curve templates to classify SN objects. In the first case, we present an updated version of the Bayesian Adaptive Template Matching program (BATM). To address some shortcomings of that strictly Bayesian approach, we introduce a method for Supernova Ontology with Fuzzy Templates (SOFT), which utilizes fuzzy set theory for the definition and combination of SN light-curve models. For well-sampled light curves with a modest signal-to-noise ratio (S/N >10), the SOFT method can correctly separate thermonuclear (Type Ia) SNe from core collapse SNe with >=98% accuracy. In addition, the SOFT method has the potential to classify SNe into sub-types, providing photometric identification of very rare or peculiar explosions. The accuracy and precision of the SOFT method are verified using Monte Carlo simulations as well as real SN light curves from the Sloan Digital Sky Survey and the SuperNova Legacy Survey. In a subsequent paper, the SOFT method is extended to address the problem of parameter estimation, providing estimates of redshift, distance, and host galaxy extinction without any spectroscopy.

  16. A relativistic type Ibc supernova without a detected gamma-ray burst.

    PubMed

    Soderberg, A M; Chakraborti, S; Pignata, G; Chevalier, R A; Chandra, P; Ray, A; Wieringa, M H; Copete, A; Chaplin, V; Connaughton, V; Barthelmy, S D; Bietenholz, M F; Chugai, N; Stritzinger, M D; Hamuy, M; Fransson, C; Fox, O; Levesque, E M; Grindlay, J E; Challis, P; Foley, R J; Kirshner, R P; Milne, P A; Torres, M A P

    2010-01-28

    Long duration gamma-ray bursts (GRBs) mark the explosive death of some massive stars and are a rare sub-class of type Ibc supernovae. They are distinguished by the production of an energetic and collimated relativistic outflow powered by a central engine (an accreting black hole or neutron star). Observationally, this outflow is manifested in the pulse of gamma-rays and a long-lived radio afterglow. Until now, central-engine-driven supernovae have been discovered exclusively through their gamma-ray emission, yet it is expected that a larger population goes undetected because of limited satellite sensitivity or beaming of the collimated emission away from our line of sight. In this framework, the recovery of undetected GRBs may be possible through radio searches for type Ibc supernovae with relativistic outflows. Here we report the discovery of luminous radio emission from the seemingly ordinary type Ibc SN 2009bb, which requires a substantial relativistic outflow powered by a central engine. A comparison with our radio survey of type Ibc supernovae reveals that the fraction harbouring central engines is low, about one per cent, measured independently from, but consistent with, the inferred rate of nearby GRBs. Independently, a second mildly relativistic supernova has been reported. PMID:20110995

  17. VLA radio upper limit on Type IIn Supernova 2008S

    NASA Astrophysics Data System (ADS)

    Chandra, Poonam; Soderberg, Alicia

    2008-02-01

    Poonam Chandra and Alicia Soderberg report on behalf of a larger collaboration: We observed type IIn supernova SN 2008S (CBET 1234) with the Very Large Array (VLA) on 2008, February 10.62 UT. We do not detect any radio emission at the supernova position (CBET 1234). The flux density at the supernova position is -62 +/- 36 uJy.

  18. NOT spectroscopic classification of two supernovae

    NASA Astrophysics Data System (ADS)

    Taddia, F.; Stritzinger, M. D.

    2015-09-01

    We report the following supernova classifications. Targets were supplied by the All Sky Automated Survey for SuperNovae ASAS-SN (see Shappee et al. 2014, ApJ, 788, 48 and http://www.astronomy.ohio-state.edu/~assassin/index.shtml).

  19. Asiago spectroscopic classification of SN 2016eob

    NASA Astrophysics Data System (ADS)

    Ochner, P.; Tomasella, G. Terreran L.; Pastorello, A.; Benetti, S.; Cappellaro, E.; Elias-Rosa, N.; Turatto, M.; Yang, S.

    2016-08-01

    The Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) reports the spectroscopic classification of SN 2016eob. The transient was discovered by Leonini et al. 2016, TNS Astronomical Transient Report No. 3994, Italian Supernovae Search Project (ISSP), on UT 2016-08-03.11 in the galaxy UGC00005 (2 other supernovae exploded in this host: SN 2000da, SN 2003lq).

  20. Supernova Shocks and the Gamma-Ray Burst Connection

    NASA Astrophysics Data System (ADS)

    Chevalier, Roger

    We propose projects on the nature of low luminosity gamma-ray bursts (GRBs) and the X-ray emission from strongly interacting supernovae. The class of nearby, low luminosity GRBs with associated supernovae can be studied in detail and probably share physical processes with cosmological bursts. The particular view of low luminosity events to be explored here attributes the X-ray thermal emission to a mildly relativistic flow from a central engine, the early thermal optical emission to the shocked ejecta from a star that has undergone an eruptive event, and the radio emission to the interaction of the mildly relativistic flow with the surrounding medium. We will develop models for this scenario, including the propagation of the collimated flow through the progenitor star and the eventual transition to spherical, nonrelativistic flow in the surrounding medium. The transient event associated with SN 2008D shows similarities to the low luminosity GRBs and will be considered as an especially low energy event. The topic of X- ray supernovae builds on the growing evidence for the interaction of supernovae with very dense circumstellar matter lost within years of the supernova event. A viscous shock is expected even when the shock wave is at moderate optical depth, but the escape of X-ray emission from hot gas is complicated by a number of factors, including changes in absorption by photoionization and Comptonization of energetic photons. There may be circumstances where no emission escapes below 10 keV, but does at 10's of keV. The complex physical situation gives diagnostics on the progenitor star and its dense wind can be obtained. This research is especially relevant to the Swift, Chandra, and XMM missions, as well as the future NuSTAR mission.

  1. The dark energy survey Y1 supernova search: Survey strategy compared to forecasts and the photometric type Is SN volumetric rate

    NASA Astrophysics Data System (ADS)

    Fischer, John Arthur

    For 70 years, the physics community operated under the assumption that the expansion of the Universe must be slowing due to gravitational attraction. Then, in 1998, two teams of scientists used Type Ia supernovae to discover that cosmic expansion was actually acceler- ating due to a mysterious "dark energy." As a result, Type Ia supernovae have become the most cosmologically important transient events in the last 20 years, with a large amount of effort going into their discovery as well as understanding their progenitor systems. One such probe for understanding Type Ia supernovae is to use rate measurements to de- termine the time delay between star formation and supernova explosion. For the last 30 years, the discovery of individual Type Ia supernova events has been accelerating. How- ever, those discoveries were happening in time-domain surveys that probed only a portion of the redshift range where expansion was impacted by dark energy. The Dark Energy Survey (DES) is the first project in the "next generation" of time-domain surveys that will discovery thousands of Type Ia supernovae out to a redshift of 1.2 (where dark energy be- comes subdominant) and DES will have better systematic uncertainties over that redshift range than any survey to date. In order to gauge the discovery effectiveness of this survey, we will use the first season's 469 photometrically typed supernovee and compare it with simulations in order to update the full survey Type Ia projections from 3500 to 2250. We will then use 165 of the 469 supernovae out to a redshift of 0.6 to measure the supernovae rate both as a function of comoving volume and of the star formation rate as it evolves with redshift. We find the most statistically significant prompt fraction of any survey to date (with a 3.9? prompt fraction detection). We will also reinforce the already existing tension in the measurement of the delayed fraction between high (z > 1.2) and low red- shift rate measurements, where we find no

  2. A Deep Search with the Hubble Space Telescope for Late-Time Supernova Signatures in the Hosts of XRF 011030 and XRF 020427

    NASA Technical Reports Server (NTRS)

    Levan, Andrew; Patel, Sandeep; Kouveliotou, Chryssa; Fruchter, Andrew; Rhoads, James; Rol, Evert; Ramirez-Ruiz, Enrico; Gorosabel, Javier; Hiorth, Jens; Wijers, Ralph

    2005-01-01

    X-ray flashes (XRFs) are, like gamma-ray bursts (GRBs), thought to signal the collapse of massive stars in distant galaxies. Many models posit that the isotropic equivalent energies of XRFs are lower than those for GRBs, such that they are visible fiom a reduced range of distances when compared with GRBs. Here we present the results of two-epoch Hubble Space Telescope imaging of two XRFs. These images, taken approximately 45 and 200 days postburst, reveal no evidence of an associated supernova in either case. Supernovae such as SN 1998bw would have been visible out to z approximately 1.5 in each case, while fainter supernovae such as SN 2002ap would have been visible to z approximately 1. If the XRFs lie at such large distances, their energies would not fit the observed correlation between the GRB peak energy and isotropic energy release (E(sub p) proportional to E(sub iso)(sup 1/2), in which soft bursts are less energetic. We conclude that, should these XRFs reside at low redshifts (z less than 0.6), either their line of sight is heavily extinguished, they are associated with extremely faint supernovae, or, unlike GRBs, these XRFs do not have temporally coincident supernovae.

  3. The Most Luminous Supernovae

    NASA Astrophysics Data System (ADS)

    Sukhbold, Tuguldur; Woosley, S. E.

    2016-04-01

    Recent observations have revealed a stunning diversity of extremely luminous supernovae, seemingly increasing in radiant energy without bound. We consider simple approximate limits for what existing models can provide for the peak luminosity and total radiated energy for non-relativistic, isotropic stellar explosions. The brightest possible supernova is a Type I explosion powered by a sub-millisecond magnetar with field strength B ∼ few × {10}13 G. In extreme cases, such models might reach a peak luminosity of 2× {10}46 {erg} {{{s}}}-1 and radiate a total energy of up to 4× {10}52 {erg}. Other less luminous models are also explored, including prompt hyper-energetic explosions in red supergiants, pulsational-pair instability supernovae, pair-instability supernovae, and colliding shells. Approximate analytic expressions and limits are given for each case. Excluding magnetars, the peak luminosity is near 3× {10}44 {erg} {{{s}}}-1 for the brightest models and the corresponding limit on total radiated energy is 3× {10}51 {erg}. Barring new physics, supernovae with a light output over 3× {10}51 erg must be rotationally powered, either during the explosion itself or after, the most obvious candidate being a rapidly rotating magnetar. A magnetar-based model for the recent transient event, ASASSN-15lh is presented that strains, but does not exceed the limits of what the model can provide.

  4. Type Ia supernova rate studies from the SDSS-II Supernova Study

    SciTech Connect

    Dilday, Benjamin

    2008-08-01

    The author presents new measurements of the type Ia SN rate from the SDSS-II Supernova Survey. The SDSS-II Supernova Survey was carried out during the Fall months (Sept.-Nov.) of 2005-2007 and discovered ~ 500 spectroscopically confirmed SNe Ia with densely sampled (once every ~ 4 days), multi-color light curves. Additionally, the SDSS-II Supernova Survey has discovered several hundred SNe Ia candidates with well-measured light curves, but without spectroscopic confirmation of type. This total, achieved in 9 months of observing, represents ~ 15-20% of the total SNe Ia discovered worldwide since 1885. The author describes some technical details of the SN Survey observations and SN search algorithms that contributed to the extremely high-yield of discovered SNe and that are important as context for the SDSS-II Supernova Survey SN Ia rate measurements.

  5. ASASSN-16gf: Discovery of A Supernova in CGCG 104-069

    NASA Astrophysics Data System (ADS)

    Fausnaugh, M.; Garnavich, P.; Zinn, J.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.

    2016-06-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a supernova in the galaxy CGCG 104-069.

  6. ASASSN-16eo: Discovery of A Supernova in an Uncatalogued Galaxy

    NASA Astrophysics Data System (ADS)

    Strader, J.; Chomiuk, L.; Shishkovsky, L.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.

    2016-04-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new supernova in an uncatalogued galaxy.

  7. Supernova hydrodynamicas experiments using the Nova laser

    SciTech Connect

    Remington, B.A.; Glendinning, S.G.; Estabrook, K.

    1997-07-01

    We are developing experiments using the Nova laser to investigate (1) compressible nonlinear hydrodynamic mixing relevant to the first few hours of the supernova (SN) explosion and (2) ejecta-ambient plasma interactions relevant to the early SN remnant phase. The experiments and astrophysical implications are discussed.

  8. Recent developments in supernova research with VLBI

    NASA Astrophysics Data System (ADS)

    Bartel, Norbert; Bietenholz, Michael F.

    2014-01-01

    Very long baseline interferometry (VLBI) observations during the last 30 years have resolved many supernovae and provided detailed measurements of the expansion velocity and deceleration. Such measurements are useful for estimating the radial density profiles of both the ejecta and the circumstellar medium left over from the progenitor. VLBI measurements are also the most direct way of confirming the relativistic expansion velocities thought to occur in supernovae associated with gamma-ray bursts. Well-resolved images of a few supernovae have been obtained, and the interaction of the ejecta as it expands into the circumstellar medium could be monitored in detail. We discuss recent results, for SN 1979C, SN 1986J, and SN 1993J, and note that updated movies of the latter two of the supernovae from soon after the explosion to the present are available from the first author's personal website.

  9. Black Hole Physics and Astrophysics: The GRB-Supernova Connection and URCA-1 - URCA-2

    NASA Astrophysics Data System (ADS)

    Ruffini, R.; Bernardini, M. G.; Bianco, C. L.; Vitagliano, L.; Xue, S.-S.; Chardonnet, P.; Fraschetti, F.; Gurzadyan, V.

    2006-02-01

    We outline the confluence of three novel theoretical fields in our modeling of Gamma-Ray Bursts (GRBs): 1) the ultrarelativistic regime of a shock front expanding with a Lorentz gamma factor ~ 300; 2) the quantum vacuum polarization process leading to an electron-positron plasma originating the shock front; and 3) the general relativistic process of energy extraction from a black hole originating the vacuum polarization process. There are two different classes of GRBs: the long GRBs and the short GRBs. We here address the issue of the long GRBs. The theoretical understanding of the long GRBs has led to the detailed description of their luminosities in fixed energy bands, of their spectral features and made also possible to probe the astrophysical scenario in which they originate. We are specially interested, in this report, to a subclass of long GRBs which appear to be accompanied by a supernova explosion. We are considering two specific examples: GRB980425/SN1998bw and GRB030329/SN2003dh. While these supernovae appear to have a standard energetics of 1049 ergs, the GRBs are highly variable and can have energetics 104 - 105 times larger than the ones of the supernovae. Moreover, many long GRBs occurs without the presence of a supernova. It is concluded that in no way a GRB can originate from a supernova. The precise theoretical understanding of the GRB luminosity we present evidence, in both these systems, the existence of an independent component in the X-ray emission, usually interpreted in the current literature as part of the GRB afterglow. This component has been observed by Chandra and XMM to have a strong decay on scale of months. We have named here these two sources respectively URCA-1 and URCA-2, in honor of the work that George Gamow and Mario Shoenberg did in 1939 in this town of Urca identifying the basic mechanism, the Urca processes, leading to the process of gravitational collapse and the formation of a neutron star and a supernova. The further

  10. On relative supernova rates and nucleosynthesis roles

    NASA Technical Reports Server (NTRS)

    Arnett, W. David; Schramm, David N.; Truran, James W.

    1988-01-01

    It is shown that the Ni-56-Fe-56 observed in SN 1987A argues that core collapse supernovae may be responsible for more that 50 percent of the iron in the galaxy. Furthermore it is argued that the time averaged rate of thermonuclear driven Type I supernovae may be at least an order of magnitude lower than the average rate of core collapse supernovae. The present low rate of Type II supernovae (below their time averaged rate of approx. 1/10 yr) is either because the past rate was much higher because many core collapse supernovae are dim like SN 1987A. However, even in this latter case they are only an order of magnitude dimmer that normal Type II's due to the contribution of Ni-56 decay to the light curve.

  11. On relative supernova rates and nucleosynthesis roles

    NASA Technical Reports Server (NTRS)

    Arnett, W. David; Schramm, David N.; Truran, James W.

    1989-01-01

    It is shown that the Ni-56-Fe-56 observed in SN 1987A argues that core collapse supernovae may be responsible for more than 50 percent of the iron in the galaxy. Furthermore it is argued that the time averaged rate of thermonuclear driven Type I supernovae may be at least an order of magnitude lower than the average rate of core collapse supernovae. The present low rate of Type II supernovae (below their time averaged rate of approx. 1/10 yr) is either because the past rate was much higher because many core collapse supernovae are dim like SN 1987A. However, even in this latter case they are only an order of magnitude dimmer that normal Type II's due to the contribution of Ni-56 decay to the light curve.

  12. THE UNUSUAL TEMPORAL AND SPECTRAL EVOLUTION OF THE TYPE IIn SUPERNOVA 2011ht

    SciTech Connect

    Roming, P. W. A.; Bayless, A. J.; Pritchard, T. A.; Prieto, J. L.; Kochanek, C. S.; Beacom, J. F.; Pogge, R. W.; Stoll, R.; Shappee, B. J.; Stanek, K. Z.; Szczygiel, D. M.; Fryer, C. L.; Davidson, K.; Humphreys, R. M.; Brown, P. J.; Holland, S. T.; Immler, S.; Kuin, N. P. M.; Oates, S. R.; Pojmanski, G.

    2012-06-01

    We present very early UV to optical photometric and spectroscopic observations of the peculiar Type IIn supernova (SN) 2011ht in UGC 5460. The UV observations of the rise to peak are only the second ever recorded for a Type IIn SN and are by far the most complete. The SN, first classified as an SN impostor, slowly rose to a peak of M{sub V} {approx} -17 in {approx}55 days. In contrast to the {approx}2 mag increase in the v-band light curve from the first observation until peak, the UV flux increased by >7 mag. The optical spectra are dominated by strong, Balmer emission with narrow peaks (FWHM {approx} 600 km s{sup -1}), very broad asymmetric wings (FWHM {approx} 4200 km s{sup -1}), and blueshifted absorption ({approx}300 km s{sup -1}) superposed on a strong blue continuum. The UV spectra are dominated by Fe II, Mg II, Si II, and Si III absorption lines broadened by {approx}1500 km s{sup -1}. Merged X-ray observations reveal a L{sub 0.2-10} = (1.0 {+-} 0.2) Multiplication-Sign 10{sup 39} erg s{sup -1}. Some properties of SN 2011ht are similar to SN impostors, while others are comparable to Type IIn SNe. Early spectra showed features typical of luminous blue variables at maximum and during giant eruptions. However, the broad emission profiles coupled with the strong UV flux have not been observed in previous SN impostors. The absolute magnitude and energetics ({approx}2.5 Multiplication-Sign 10{sup 49} erg in the first 112 days) are reminiscent of normal Type IIn SN, but the spectra are of a dense wind. We suggest that the mechanism for creating this unusual profile could be a shock interacting with a shell of material that was ejected a year before the discovery of the SN.

  13. Extreme Supernova Models for the Super-luminous Transient ASASSN-15lh

    NASA Astrophysics Data System (ADS)

    Chatzopoulos, E.; Wheeler, J. C.; Vinko, J.; Nagy, A. P.; Wiggins, B. K.; Even, W. P.

    2016-09-01

    The recent discovery of the unprecedentedly super-luminous transient ASASSN-15lh (or SN 2015L) with its UV-bright secondary peak challenges all the power-input models that have been proposed for super-luminous supernovae. Here we examine some of the few viable interpretations of ASASSN-15lh in the context of a stellar explosion, involving combinations of one or more power inputs. We model the light curve of ASASSN-15lh with a hybrid model that includes contributions from magnetar spin-down energy and hydrogen-poor circumstellar interaction. We also investigate models of pure circumstellar interaction with a massive hydrogen-deficient shell and discuss the lack of interaction features in the observed spectra. We find that, as a supernova, ASASSN-15lh can be best modeled by the energetic core-collapse of an ∼40 M ⊙ star interacting with a hydrogen-poor shell of ∼20 M ⊙. The circumstellar shell and progenitor mass are consistent with a rapidly rotating pulsational pair-instability supernova progenitor as required for strong interaction following the final supernova explosion. Additional energy injection by a magnetar with an initial period of 1–2 ms and magnetic field of 0.1–1 × 1014 G may supply the excess luminosity required to overcome the deficit in single-component models, but this requires more fine-tuning and extreme parameters for the magnetar, as well as the assumption of efficient conversion of magnetar energy into radiation. We thus favor a single-input model where the reverse shock formed in a strong SN ejecta–circumstellar matter interaction following a very powerful core-collapse SN explosion can supply the luminosity needed to reproduce the late-time UV-bright plateau.

  14. The Impact of a Supernova Remnant on Fast Radio Bursts

    NASA Astrophysics Data System (ADS)

    Piro, Anthony L.

    2016-06-01

    Fast radio bursts (FRBs) are millisecond bursts of radio radiation whose progenitors, so far, remain mysterious. Nevertheless, the timescales and energetics of these events have lead to many theories associating FRBs with young neutron stars (NSs). Motivated by this, I explore the interaction of FRBs with young supernova remnants (SNRs), and I discuss the potential observational consequences and constraints of such a scenario. As the supernova (SN) ejecta plows into the interstellar medium (ISM), a reverse shock is generated that passes back through the material and ionizes it. This leads to a dispersion measure (DM) associated with the SNR as well as a time derivative for DM. The times when DM is high are generally overshadowed by free–free absorption, which, depending on the mass of the ejecta and the density of the ISM, may be probed at frequencies of 400 {{MHz}}–1.4 {{GHz}} on timescales of ∼100–500 years after the SN. Magnetic fields generated at the reverse shock may be high enough to explain Faraday rotation that has been measured for one FRB. If FRBs are powered by the spin energy of a young NS (rather than by magnetic energy), the NS must have a magnetic field ≲ {10}11{--}{10}12 {{G}} to ensure that it does not spin down too quickly while the SNR is still optically thick at radio frequencies. In the future, once there are distance measurements to FRBs and their energetics are better understood, the spin of the NS can also be constrained.

  15. Explosive Nucleosynthesis in Supernovae and Hypernovae

    NASA Astrophysics Data System (ADS)

    Nomoto, Ken'ichi; Moriya, Takashi; Tominaga, Nozomu

    2010-06-01

    We review the properties of supernovae (SNe) as a function of the progenitor's mass M. (1) 8-10 Msolar stars are super-AGB stars and resultant electron capture SNe may be Faint supernovae like Type IIn SN 2008S. (2) 10-13 Msolar stars undergo Fe-core collapse to form neutron stars (NSs) and Faint supernovae. (3) 13 Msolar-MBN stars undergo Fe-core collapse to form NSs and normal core-collapse supernovae. (4) MBN-90 Msolar stars undergo Fe-core collapse to form Black Holes. Resultant supernovae are bifurcate into Hypernovae and Faint supernovae. (5) 90-140 Msolar stars produce Luminous SNe, like SNe 2007 bi and 2006 gy (6) 140-300 Msolar stars become pair-instability supernovae which could be Luminous supernovae (SNe 2007 bi and 2006 gy). (7) Very massive stars with M>~300 Msolar undergo core-collapse to form intermediate mass black holes. Some SNe could be more Luminous supernovae (like SN 2006 gy).

  16. Supernova Acceleration Probe: Studying Dark Energy with Type Ia Supernovae

    SciTech Connect

    Albert, J.; Aldering, G.; Allam, S.; Althouse, W.; Amanullah, R.; Annis, J.; Astier, P.; Aumeunier, M.; Bailey, S.; Baltay, C.; Barrelet, E.; Basa, S.; Bebek, C.; Bergstom, L.; Bernstein, G.; Bester, M.; Besuner, B.; Bigelow, B.; Blandford, R.; Bohlin, R.; Bonissent, A.; /Caltech /LBL, Berkeley /Fermilab /SLAC /Stockholm U. /Paris, IN2P3 /Marseille, CPPM /Marseille, Lab. Astrophys. /Yale U. /Pennsylvania U. /UC, Berkeley /Michigan U. /Baltimore, Space Telescope Sci. /Indiana U. /Caltech, JPL /Australian Natl. U., Canberra /American Astron. Society /Chicago U. /Cambridge U. /Saclay /Lyon, IPN

    2005-08-08

    The Supernova Acceleration Probe (SNAP) will use Type Ia supernovae (SNe Ia) as distance indicators to measure the effect of dark energy on the expansion history of the Universe. (SNAP's weak-lensing program is described in a separate White Paper.) The experiment exploits supernova distance measurements up to their fundamental systematic limit; strict requirements on the monitoring of each supernova's properties leads to the need for a space-based mission. Results from pre-SNAP experiments, which characterize fundamental SN Ia properties, will be used to optimize the SNAP observing strategy to yield data, which minimize both systematic and statistical uncertainties. With early R&D funding, we have achieved technological readiness and the collaboration is poised to begin construction. Pre-JDEM AO R&D support will further reduce technical and cost risk. Specific details on the SNAP mission can be found in Aldering et al. (2004, 2005). The primary goal of the SNAP supernova program is to provide a dataset which gives tight constraints on parameters which characterize the dark-energy, e.g. w{sub 0} and w{sub a} where w(a) = w{sub 0} + w{sub a}(1-a). SNAP data can also be used to directly test and discriminate among specific dark energy models. We will do so by building the Hubble diagram of high-redshift supernovae, the same methodology used in the original discovery of the acceleration of the expansion of the Universe that established the existence of dark energy (Perlmutter et al. 1998; Garnavich et al. 1998; Riess et al. 1998; Perlmutter et al. 1999). The SNAP SN Ia program focuses on minimizing the systematic floor of the supernova method through the use of characterized supernovae that can be sorted into subsets based on subtle signatures of heterogeneity. Subsets may be defined based on host-galaxy morphology, spectral-feature strength and velocity, early-time behavior, inter alia. Independent cosmological analysis of each subset of ''like'' supernovae can be

  17. Non-LTE models for synthetic spectra of type Ia supernovae. III. An accelerated lambda-iteration procedure for the mutual interaction of strong spectral lines in SN Ia models with and without energy deposition

    NASA Astrophysics Data System (ADS)

    Pauldrach, A. W. A.; Hoffmann, T. L.; Hultzsch, P. J. N.

    2014-09-01

    Context. In type Ia supernova (SN Ia) envelopes a huge number of lines of different elements overlap within their thermal Doppler widths, and this problem is exacerbated by the circumstance that up to 20% of these lines can have a line optical depth higher than 1. The stagnation of the lambda iteration in such optically thick cases is one of the fundamental physical problems inherent in the iterative solution of the non-LTE problem, and the failure of a lambda iteration to converge is a point of crucial importance whose physical significance must be understood completely. Aims: We discuss a general problem related to radiative transfer under the physical conditions of supernova ejecta that involves a failure of the usual non-LTE iteration scheme to converge when multiple strong opacities belonging to different physical transitions come together, similar to the well-known situation where convergence is impaired even when only a single process attains high optical depths. The convergence problem is independent of the chosen frequency and depth grid spacing, independent of whether the radiative transfer is solved in the comoving or observer's frame, and independent of whether a common complete-linearization scheme or a conventional accelerated lambda iteration (ALI) is used. The problem appears when all millions of line transitions required for a realistic description of SN Ia envelopes are treated in the frame of a comprehensive non-LTE model. The only solution to this problem is a complete-linearization approach that considers all ions of all elements simultaneously, or an adequate generalization of the established ALI technique that accounts for the mutual interaction of the strong spectral lines of different elements and which thereby unfreezes the "stuck" state of the iteration. Methods: The physics of the atmospheres of SN Ia are strongly affected by the high-velocity expansion of the ejecta, which dominates the formation of the spectra at all wavelength ranges

  18. Software Based Supernova Recognition

    NASA Astrophysics Data System (ADS)

    Walters, Stephen M.

    2014-05-01

    This paper describes software for detecting Supernova (SN) in images. The software can operate in real-time to discover SN while data is being collected so the instrumentation can immediately be re-tasked to perform spectroscopy or photometry of a discovery. Because the instrumentation captures two images per minute, the realtime budget is constrained to 30 seconds per target, a challenging goal. Using a set of two to four images, the program creates a "Reference" (REF) image and a "New" (NEW) image where all images are used in both NEW and REF but any SN survives the combination process only in the NEW image. This process produces good quality images having similar noise characteristics but without artifacts that might be interpreted as SN. The images are then adjusted for seeing and brightness differences using a variant of Tomaney and Crotts method of Point Spread Function (PSF) matching after which REF is subtracted from NEW to produce a Difference (DIF) image. A Classifier is then trained on a grid of artificial SN to estimate the statistical properties of four attributes and used in a process to mask false positives that can be clearly identified as such. Further training to avoid any remaining false positives sets the range, in standard deviations for each attribute, that the Classifier will accept as a valid SN. This training enables the Classifier to discriminate between SN and most subtraction residue. Lastly, the DIF image is scanned and measured by the Classifier to find locations where all four properties fall within their acceptance ranges. If multiple locations are found, the one best conforming to the training estimates is chosen. This location is then declared as a Candidate SN, the instrumentation re-tasked and the operator notified.

  19. An outburst from a massive star 40 days before a supernova explosion

    NASA Astrophysics Data System (ADS)

    Ofek, E. O.; Sullivan, M.; Cenko, S. B.; Kasliwal, M. M.; Gal-Yam, A.; Kulkarni, S. R.; Arcavi, I.; Bildsten, L.; Bloom, J. S.; Horesh, A.; Howell, D. A.; Filippenko, A. V.; Laher, R.; Murray, D.; Nakar, E.; Nugent, P. E.; Silverman, J. M.; Shaviv, N. J.; Surace, J.; Yaron, O.

    2013-02-01

    Some observations suggest that very massive stars experience extreme mass-loss episodes shortly before they explode as supernovae, as do several models. Establishing a causal connection between these mass-loss episodes and the final explosion would provide a novel way to study pre-supernova massive-star evolution. Here we report observations of a mass-loss event detected 40 days before the explosion of the type IIn supernova SN 2010mc (also known as PTF 10tel). Our photometric and spectroscopic data suggest that this event is a result of an energetic outburst, radiating at least 6 × 1047 erg of energy and releasing about 10-2 solar masses of material at typical velocities of 2,000 km s-1. The temporal proximity of the mass-loss outburst and the supernova explosion implies a causal connection between them. Moreover, we find that the outburst luminosity and velocity are consistent with the predictions of the wave-driven pulsation model, and disfavour alternative suggestions.

  20. A Strange Supernova with a Gamma-Ray Burst

    NASA Astrophysics Data System (ADS)

    1998-10-01

    1998bw is obviously an unusual supernova. It is therefore of particular significance that a Gamma-Ray Burst was observed from the same sky region just before it was discovered in optical light. It is very unlikely that these two very rare events would happen in the same region of the sky without being somehow related. Most astronomers therefore tend to believe that the gamma-rays do indeed originate in the supernova explosion. But can a single supernova be sufficiently energetic to produce a powerful Gamma-Ray Burst? New theoretical calculations, also published today in Nature, indicate that this may be so. Moreover, if the Gamma-Ray Burst observed on April 25 did originate in this supernova that is located in a relatively nearby galaxy, it was intrinsically much fainter than some of the other Gamma-Ray Bursts that are known to have taken place in extremely distant galaxies. The main idea is that while the centres of most other supernovae collapse into neutron stars at the moment of explosion, a black hole was created in a very massive star consisting mostly of carbon and oxygen. If so, a very strong shockwave may be produced that is capable of generating the observed gamma rays. A comparison of synthetic spectra from such a supernova model, based on a new spectrum-modelling technique developed by Leon Lucy at the ESA/ESO Space Telescope/European Coordinating Facility (ST/ECF), with the spectra of SN 1998bw observed at La Silla, show good agreement, thus lending credibility to the new models. Future work Much data has already been collected at ESO on the strange supernova SN 1998bw . More observations will be obtained by the astronomers at the ESO observatories in the future during a long-term monitoring programme of SN 1998bw . There is a good chance that this effort will ultimately provide fundamental information on the explosion mechanism and the nature of the progenitor star of this exceptional object. This supernova's connection with a Gamma-Ray Burst will

  1. Spectral ID of snASASSN-14jb

    NASA Astrophysics Data System (ADS)

    Challis, Peter

    2014-10-01

    The spectrum has a very blue continuum with emission of H Alpha, H Beta, H Gamma, H Delta and He II 4686. Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows a reasonable match to the spectrum of type II supernova SN2005cs.

  2. Radio emission from supernovae.

    NASA Astrophysics Data System (ADS)

    Weiler, K. W.; Panagia, N.; Sramek, R. A.; Van Dyk, S. D.; Stockdale, C. J.; Williams, C. L.

    Study of radio supernovae over the past 30 years includes more than three dozen detected objects and more than 150 upper limits. From this work it is possible to identify classes of radio properties, demonstrate conformance to and deviations from existing models, estimate the density and structure of the circumstellar material and, by inference, the evolution of the presupernova stellar wind, and reveal the last stages of stellar evolution before explosion. Along with reviewing these general properties of the radio emission from supernovae, we present our extensive observations of the radio emission from supernova (SN) 1993J in M 81 (NGC 3031) made with the Very Large Array and other radio telescopes. The SN 1993J radio emission evolves regularly in both time and frequency, and the usual interpretation in terms of shock interaction with a circumstellar medium (CSM) formed by a pre-supernova stellar wind describes the observations rather well considering the complexity of the phenomenon. However: 1) The highest frequency measurements at 85 - 110 GHz at early times (<40 days) are not well fitted by the parameterization which describes the cm wavelength measurements. 2) At a time ˜3100 days after shock breakout, the decline rate of the radio emission steepens from (t+beta ) beta ˜ -0.7 to beta ˜ -2.7 without change in the spectral index (nu +alpha ; alpha ˜ -0.81). This decline is best described not as a power-law, but as an exponential decay with an e-folding time of ˜ 1100 days. 3) The best overall fit to all of the data is a model including both non-thermal synchrotron self-absorption (SSA) and a thermal free-free absorbing (FFA) components at early times, evolving to a constant spectral index, optically thin decline rate, until a break in that decline rate at day ˜3100, as mentioned above.

  3. Discovery of Shell-Like Radio-Structure in SN 1993J

    NASA Technical Reports Server (NTRS)

    Marcaide, J.; Alberdi, A.; Ros, E.; Diamond, P.; Schmidt, B.; Shapiro, I.; Baath, L.; De Bruyn, G.; Elosegui, P.; Guirado, J.; Davis, R.; Jones, D.; Krichbaum, T.; Manntovani, F.; Preston, R.; Ratner, M.; Rius, A.; Rogers, A.; Schilizzi, R.; Trigilio, C.; Whitney, A.; Witzel, A.; Zensus, A.

    1994-01-01

    The radio-luminous supernova SN 1993J in M81 offers an unprecedented opportunity to study with high linear resolution the details of the growth of a supernova radio structure by means of the VLBI technique.

  4. The Spectroscopic Classification and Explosion Properties of SN 2009nz Associated with GRB 091127 at z = 0.490

    NASA Astrophysics Data System (ADS)

    Berger, E.; Chornock, R.; Holmes, T. R.; Foley, R. J.; Cucchiara, A.; Wolf, C.; Podsiadlowski, Ph.; Fox, D. B.; Roth, K. C.

    2011-12-01

    We present spectroscopic observations of GRB 091127 (z = 0.490) at the peak of the putative associated supernova SN 2009nz. Subtracting a late-time spectrum of the host galaxy, we isolate the contribution of SN 2009nz and uncover broad features typical of nearby gamma-ray-burst-supernovae (GRB-SNe). This establishes unambiguously that GRB 091127 was accompanied by a broad-lined Type Ic SN, and links a cosmological long burst with a standard energy release (E γ, iso ≈ 1.1 × 1052 erg) to a massive star progenitor. The spectrum of SN 2009nz closely resembles that of SN 2006aj, with SN 2003dh also providing an acceptable match, but has significantly narrower features than SNe 1998bw and 2010bh, indicative of a lower expansion velocity. The photospheric velocity inferred from the Si II λ6355 absorption feature, v ph ≈ 17, 000 km s-1, is indeed closer to that of SNe 2006aj and 2003dh than to the other GRB-SNe. Combining the measured velocity with the light curve peak brightness and width, we estimate the following nominal (maximal) explosion parameters: M Ni ≈ 0.35 (0.6) M ⊙, EK ≈ 2.3 × 1051 (8.4 × 1051) erg, and M ej ≈ 1.4 (3.5) M ⊙, similar to those of SN 2006aj. These properties indicate that SN 2009nz follows a trend of lower M Ni for GRB-SNe with lower EK and M ej. Equally important, since GRB 091127 is a typical cosmological burst, the similarity of SN 2009nz to SN 2006aj either casts doubt on the claim that XRF 060218/SN 2006aj was powered by a neutron star or indicates that the nature of the central engine is encoded in the SN properties but not in the prompt emission. Future spectra of GRB-SNe at z >~ 0.3 will shed light on the full dispersion of SN properties for standard long GRBs, on the relation between SNe associated with sub-energetic and standard GRBs, and on a potential dispersion in the associated SN types.

  5. Supernova Flashback

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Annotated Version

    The Cassiopeia A supernova's first flash of radiation makes six clumps of dust (circled in annotated version) unusually hot. The supernova remnant is the large white ball in the center. This infrared picture was taken by NASA's Spitzer Space Telescope.

  6. Centrarchid Energetics

    SciTech Connect

    Bevelhimer, Mark S; Breck, Dr. James

    2009-06-01

    This chapter contains sections titled: (1) Introduction; (2) Centrarchid bioenergetics models; (3) Food consumption and feeding energetics; (4) Metabolic rate; (5) Energetic wastes (egestion, excretion, and SDA); (6) Growth energetics; (7) Reproductive energetics; (8) Synthesis; (9) Research needs; and (10) References.

  7. UV Observations of Type Iax Supernovae

    NASA Astrophysics Data System (ADS)

    McCully, Curtis; Howell, Dale Andrew; Jha, Saurabh; Foley, Ryan; Downing, Steven; Valenti, Stefano

    2016-01-01

    Type Iax (aka SN 2002cx-like) supernovae (SNe) are fainter and have lower ejecta velocities than normal type Ia SNe, but have otherwise similar optical spectra near maximum light. It is not clear how SNe Iax are physically related to SNe Ia which are used for cosmology. A hint may come from the UV which is sensitive to the progenitor system and explosion mechanism for thermonuclear SNe. We will present SWIFT and HST UV observations of SN 2013dh, a low luminosity and low velocity SN Iax. While the broad band UV colors of SN 2013dh are bluer than the normal Ia SN 2011fe, the UV spectral features of both objects are remarkably similar (though SN 2013dh has a much lower ejecta velocity). These data, along with the detection of the progenitor system of the Iax, SN 2012Z, in pre-explosion HST images are helping us understand the physical diversity of these stellar explosions.

  8. The Detection of a Type IIn Supernova in Optical Follow-up Observations of IceCube Neutrino Events

    NASA Astrophysics Data System (ADS)

    Aartsen, M. G.; Abraham, K.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Ahrens, M.; Altmann, D.; Anderson, T.; Archinger, M.; Arguelles, C.; Arlen, T. C.; Auffenberg, J.; Bai, X.; Barwick, S. W.; Baum, V.; Bay, R.; Beatty, J. J.; Becker Tjus, J.; Becker, K.-H.; Beiser, E.; BenZvi, S.; Berghaus, P.; Berley, D.; Bernardini, E.; Bernhard, A.; Besson, D. Z.; Binder, G.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Börner, M.; Bos, F.; Bose, D.; Böser, S.; Botner, O.; Braun, J.; Brayeur, L.; Bretz, H.-P.; Brown, A. M.; Buzinsky, N.; Casey, J.; Casier, M.; Cheung, E.; Chirkin, D.; Christov, A.; Christy, B.; Clark, K.; Classen, L.; Coenders, S.; Cowen, D. F.; Cruz Silva, A. H.; Daughhetee, J.; Davis, J. C.; Day, M.; de André, J. P. A. M.; De Clercq, C.; Dembinski, H.; De Ridder, S.; Desiati, P.; de Vries, K. D.; de Wasseige, G.; de With, M.; DeYoung, T.; Díaz-Vélez, J. C.; Dumm, J. P.; Dunkman, M.; Eagan, R.; Eberhardt, B.; Ehrhardt, T.; Eichmann, B.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fahey, S.; Fazely, A. R.; Fedynitch, A.; Feintzeig, J.; Felde, J.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Flis, S.; Fuchs, T.; Glagla, M.; Gaisser, T. K.; Gaior, R.; Gallagher, J.; Gerhardt, L.; Ghorbani, K.; Gier, D.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Golup, G.; Gonzalez, J. G.; Góra, D.; Grant, D.; Gretskov, P.; Groh, J. C.; Gross, A.; Ha, C.; Haack, C.; Haj Ismail, A.; Hallgren, A.; Halzen, F.; Hansmann, B.; Hanson, K.; Hebecker, D.; Heereman, D.; Helbing, K.; Hellauer, R.; Hellwig, D.; Hickford, S.; Hignight, J.; Hill, G. C.; Hoffman, K. D.; Hoffmann, R.; Holzapfe, K.; Homeier, A.; Hoshina, K.; Huang, F.; Huber, M.; Huelsnitz, W.; Hulth, P. O.; Hultqvist, K.; In, S.; Ishihara, A.; Jacobi, E.; Japaridze, G. S.; Jero, K.; Jurkovic, M.; Kaminsky, B.; Kappes, A.; Karg, T.; Karle, A.; Kauer, M.; Keivani, A.; Kelley, J. L.; Kemp, J.; Kheirandish, A.; Kiryluk, J.; Kläs, J.; Klein, S. R.; Kohnen, G.; Koirala, R.; Kolanoski, H.; Konietz, R.; Koob, A.; Köpke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Krings, K.; Kroll, G.; Kroll, M.; Kunnen, J.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Lanfranchi, J. L.; Larson, M. J.; Lesiak-Bzdak, M.; Leuermann, M.; Leuner, J.; Lünemann, J.; Madsen, J.; Maggi, G.; Mahn, K. B. M.; Maruyama, R.; Mase, K.; Matis, H. S.; Maunu, R.; McNally, F.; Meagher, K.; Medici, M.; Meli, A.; Menne, T.; Merino, G.; Meures, T.; Miarecki, S.; Middell, E.; Middlemas, E.; Miller, J.; Mohrmann, L.; Montaruli, T.; Morse, R.; Nahnhauer, R.; Naumann, U.; Niederhausen, H.; Nowicki, S. C.; Nygren, D. R.; Obertacke, A.; Olivas, A.; Omairat, A.; O’Murchadha, A.; Palczewski, T.; Pandya, H.; Paul, L.; Pepper, J. A.; Pérez de los Heros, C.; Pfendner, C.; Pieloth, D.; Pinat, E.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Pütz, J.; Quinnan, M.; Rädel, L.; Rameez, M.; Rawlins, K.; Redl, P.; Reimann, R.; Relich, M.; Resconi, E.; Rhode, W.; Richman, M.; Richter, S.; Riedel, B.; Robertson, S.; Rongen, M.; Rott, C.; Ruhe, T.; Ryckbosch, D.; Saba, S. M.; Sabbatini, L.; Sander, H.-G.; Sandrock, A.; Sandroos, J.; Sarkar, S.; Schatto, K.; Scheriau, F.; Schimp, M.; Schmidt, T.; Schmitz, M.; Schoenen, S.; Schöneberg, S.; Schönwald, A.; Schukraft, A.; Schulte, L.; Seckel, D.; Seunarine, S.; Shanidze, R.; Smith, M. W. E.; Soldin, D.; Spiczak, G. M.; Spiering, C.; Stahlberg, M.; Stamatikos, M.; Stanev, T.; Stanisha, N. A.; Stasik, A.; Stezelberger, T.; Stokstad, R. G.; Stössl, A.; Strahler, E. A.; Ström, R.; Strotjohann, N. L.; Sullivan, G. W.; Sutherland, M.; Taavola, H.; Taboada, I.; Ter-Antonyan, S.; Terliuk, A.; Tešić, G.; Tilav, S.; Toale, P. A.; Tobin, M. N.; Tosi, D.; Tselengidou, M.; Turcati, A.; Unger, E.; Usner, M.; Vallecorsa, S.; van Eijndhoven, N.; Vandenbroucke, J.; van Santen, J.; Vanheule, S.; Veenkamp, J.; Vehring, M.; Voge, M.; Vraeghe, M.; Walck, C.; Wallraff, M.; Wandkowsky, N.; Weaver, Ch.; Wendt, C.; Westerhoff, S.; Whelan, B. J.; Whitehorn, N.; Wichary, C.; Wiebe, K.; Wiebusch, C. H.; Wille, L.; Williams, D. R.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, D. L.; Xu, X. W.; Xu, Y.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; Zoll, M.; IceCube Collaboration; Ofek, Eran O.; Kasliwal, Mansi M.; Nugent, Peter E.; Arcavi, Iair; Bloom, Joshua S.; Kulkarni, Shrinivas R.; Perley, Daniel A.; Barlow, Tom; Horesh, Assaf; Gal-Yam, Avishay; Howell, D. A.; Dilday, Ben; for the PTF Collaboration; Evans, Phil A.; Kennea, Jamie A.; for the Swift Collaboration; Burgett, W. S.; Chambers, K. C.; Kaiser, N.; Waters, C.; Flewelling, H.; Tonry, J. L.; Rest, A.; Smartt, S. J.; Pan-STARRS1 Science Consortium, for the

    2015-09-01

    The IceCube neutrino observatory pursues a follow-up program selecting interesting neutrino events in real-time and issuing alerts for electromagnetic follow-up observations. In 2012 March, the most significant neutrino alert during the first three years of operation was issued by IceCube. In the follow-up observations performed by the Palomar Transient Factory (PTF), a Type IIn supernova (SN IIn) PTF12csy was found 0.°2 away from the neutrino alert direction, with an error radius of 0.°54. It has a redshift of z = 0.0684, corresponding to a luminosity distance of about 300 Mpc and the Pan-STARRS1 survey shows that its explosion time was at least 158 days (in host galaxy rest frame) before the neutrino alert, so that a causal connection is unlikely. The a posteriori significance of the chance detection of both the neutrinos and the SN at any epoch is 2.2σ within IceCube's 2011/12 data acquisition season. Also, a complementary neutrino analysis reveals no long-term signal over the course of one year. Therefore, we consider the SN detection coincidental and the neutrinos uncorrelated to the SN. However, the SN is unusual and interesting by itself: it is luminous and energetic, bearing strong resemblance to the SN IIn 2010jl, and shows signs of interaction of the SN ejecta with a dense circumstellar medium. High-energy neutrino emission is expected in models of diffusive shock acceleration, but at a low, non-detectable level for this specific SN. In this paper, we describe the SN PTF12csy and present both the neutrino and electromagnetic data, as well as their analysis.

  9. Detection of Radio Transients from Supernovae

    NASA Astrophysics Data System (ADS)

    Schmitt, Christian

    2011-05-01

    A core-collapse supernova (SN) would produce an expanding shell of charged particles which interact with the surrounding magnetic field of the progenitor star producing a transient radio pulse. Approximately one supernova event per century is expected in a galaxy. The radio waves emitted are detectable by a new generation of low-frequency radio telescope arrays. We present details of an ongoing search for such events by the Eight-meter-wavelength Transient Array (ETA) and the Long Wavelength Array (LWA).

  10. TEM Study of Internal Crystals in Supernova Graphites

    NASA Astrophysics Data System (ADS)

    Croat, T. K.; Bernatowicz, T.; Stadermann, F. J.; Messenger, S.; Amari, S.

    2003-03-01

    A coordinated TEM and isotopic study of ten supernova (SN) graphites from the Murchison meteorite has revealed many internal grains, mostly titanium carbides (TiCs) and TiC-kamacite composite grains, which were accreted during the graphite growth.

  11. Rates and progenitors of type Ia supernovae

    SciTech Connect

    Wood-Vasey, William Michael

    2004-08-16

    The remarkable uniformity of Type Ia supernovae has allowed astronomers to use them as distance indicators to measure the properties and expansion history of the Universe. However, Type Ia supernovae exhibit intrinsic variation in both their spectra and observed brightness. The brightness variations have been approximately corrected by various methods, but there remain intrinsic variations that limit the statistical power of current and future observations of distant supernovae for cosmological purposes. There may be systematic effects in this residual variation that evolve with redshift and thus limit the cosmological power of SN Ia luminosity-distance experiments. To reduce these systematic uncertainties, we need a deeper understanding of the observed variations in Type Ia supernovae. Toward this end, the Nearby Supernova Factory has been designed to discover hundreds of Type Ia supernovae in a systematic and automated fashion and study them in detail. This project will observe these supernovae spectrophotometrically to provide the homogeneous high-quality data set necessary to improve the understanding and calibration of these vital cosmological yardsticks. From 1998 to 2003, in collaboration with the Near-Earth Asteroid Tracking group at the Jet Propulsion Laboratory, a systematic and automated searching program was conceived and executed using the computing facilities at Lawrence Berkeley National Laboratory and the National Energy Research Supercomputing Center. An automated search had never been attempted on this scale. A number of planned future large supernovae projects are predicated on the ability to find supernovae quickly, reliably, and efficiently in large datasets. A prototype run of the SNfactory search pipeline conducted from 2002 to 2003 discovered 83 SNe at a final rate of 12 SNe/month. A large, homogeneous search of this scale offers an excellent opportunity to measure the rate of Type Ia supernovae. This thesis presents a new method for

  12. Rates and progenitors of type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Wood-Vasey, William Michael

    The remarkable uniformity of Type Ia supernovae has allowed astronomers to use them as distance indicators to measure the properties and expansion history of the Universe. However, Type Ia supernovae exhibit intrinsic variation in both their spectra and observed brightness. The brightness variations have been approximately corrected by various methods, but there remain intrinsic variations that limit the statistical power of current and future observations of distant supernovae for cosmological purposes. There may be systematic effects in this residual variation that evolve with redshift and thus limit the cosmological power of SN Ia luminosity-distance experiments. To reduce these systematic uncertainties, we need a deeper understanding of the observed variations in Type Ia supernovae. Toward this end, the Nearby Supernova Factory has been designed to discover hundreds of Type Ia supernovae in a systematic and automated fashion and study them in detail. This project will observe these supernovae spectrophotometrically to provide the homogeneous high-quality data set necessary to improve the understanding and calibration of these vital cosmological yardsticks. >From 1998 to 2003, in collaboration with the Near-Earth Asteroid Tracking group at the Jet Propulsion Laboratory, a systematic and automated searching program was conceived and executed using the computing facilities at Lawrence Berkeley National Laboratory and the National Energy Research Supercomputing Center. An automated search had never been attempted on this scale. A number of planned future large supernovae projects are predicated on the ability to find supernovae quickly, reliably, and efficiently in large datasets. A prototype run of the SNfactory search pipeline conducted from 2002 to 2003 discovered 83 SNe at a final rate of 12 SNe/month. A large, homogeneous search of this scale offers an excellent opportunity to measure the rate of Type Ia supernovae. This thesis presents a new method for

  13. What powers the 3000-day light curve of SN 2006gy?

    NASA Astrophysics Data System (ADS)

    Fox, Ori D.; Smith, Nathan; Ammons, S. Mark; Andrews, Jennifer; Bostroem, K. Azalee; Cenko, S. Bradley; Clayton, Geoffrey C.; Dwek, Eli; Filippenko, Alexei V.; Gallagher, Joseph S.; Kelly, Patrick L.; Mauerhan, Jon C.; Miller, Adam A.; Van Dyk, Schuyler D.

    2015-12-01

    SN 2006gy was the most luminous supernova (SN) ever observed at the time of its discovery and the first of the newly defined class of superluminous supernovae (SLSNe). The extraordinary energetics of SN 2006gy and all SLSNe (>1051 erg) require either atypically large explosion energies (e.g. pair-instability explosion) or the efficient conversion of kinetic into radiative energy (e.g. shock interaction). The mass-loss characteristics can therefore offer important clues regarding the progenitor system. For the case of SN 2006gy, both a scattered and thermal light echo from circumstellar material (CSM) have been reported at later epochs (day ˜800), ruling out the likelihood of a pair-instability event and leading to constraints on the characteristics of the CSM. Owing to the proximity of the SN to the bright host-galaxy nucleus, continued monitoring of the light echo has not been trivial, requiring the high resolution offered by the Hubble Space Telescope (HST) or ground-based adaptive optics (AO). Here, we report detections of SN 2006gy using HST and Keck AO at ˜3000 d post-explosion and consider the emission mechanism for the very late-time light curve. While the optical light curve and optical spectral energy distribution are consistent with a continued scattered-light echo, a thermal echo is insufficient to power the K'-band emission by day 3000. Instead, we present evidence for late-time infrared emission from dust that is radiatively heated by CSM interaction within an extremely dense dust shell, and we consider the implications on the CSM characteristics and progenitor system.

  14. Analysis of IUE Observations of Supernovae

    NASA Technical Reports Server (NTRS)

    Kirshner, Robert P.

    1996-01-01

    This program supported the analysis of IUE observations of supernovae. One aspect was a Target-of-Opportunity program to observe bright supernovae which was applied to SN 1993J in M81, and another was continuing analysis of the IUE data from SN 1987A. Because of its quick response time, the IUE satellite has continued to provide useful data on the ultraviolet spectra of supernovae. Even after the launch of the Hubble Space Telescope, which has much more powerful ultraviolet spectrometers, the IUE has enabled us to obtain early and frequent measurements of ultraviolet radiation: this information has been folded in with our HST data to create unique observations of supernova which can be interpreted to give powerful constraints on the physical properties of the exploding stars. Our chief result in the present grant period was the completion of a detailed reanalysis of the data on the circumstellar shell of SN 1987A. The presence of narrow high-temperature mission lines from nitrogen-rich gas close to SN 1987A has been the principal observational constraint on the evolution of the supernova's progenitor. Our new analysis shows that the onset of these lines, their rise to maximum, and their subsequent fading can be understood in the context of a model for the photoionization of circumstellar matter.

  15. Supernova models

    SciTech Connect

    Woosley, S.E.; Weaver, T.A.

    1980-01-01

    Recent progress in understanding the observed properties of Type I supernovae as a consequence of the thermonuclear detonation of white dwarf stars and the ensuing decay of the /sup 56/Ni produced therein is reviewed. Within the context of this model for Type I explosions and the 1978 model for Type II explosions, the expected nucleosynthesis and gamma-line spectra from both kinds of supernovae are presented. Finally, a qualitatively new approach to the problem of massive star death and Type II supernovae based upon a combination of rotation and thermonuclear burning is discussed.

  16. The nearby supernova factory

    SciTech Connect

    Wood-Vasey, W.M.; Aldering, G.; Lee, B.C.; Loken, S.; Nugent, P.; Perlmutter, S.; Siegrist, J.; Wang, L.; Antilogus, P.; Astier, P.; Hardin, D.; Pain, R.; Copin, Y.; Smadja, G.; Gangler, E.; Castera, A.; Adam, G.; Bacon, R.; Lemonnier, J.-P.; Pecontal, A.; Pecontal, E.; Kessler, R.

    2004-01-23

    The Nearby Supernova Factory (SNfactory) is an ambitious project to find and study in detail approximately 300 nearby Type Ia supernovae (SNe Ia) at redshifts 0.03 < z < 0.08. This program will provide an exceptional data set of well-studied SNe in the nearby smooth Hubble flow that can be used as calibration for the current and future programs designed to use SNe to measure the cosmological parameters. The first key ingredient for this program is a reliable supply of Hubble-flow SNe systematically discovered in unprecedented numbers using the same techniques as those used in distant SNe searches. In 2002, 35 SNe were found using our test-bed pipeline for automated SN search and discovery. The pipeline uses images from the asteroid search conducted by the Near Earth Asteroid Tracking group at JPL. Improvements in our subtraction techniques and analysis have allowed us to increase our effective SN discovery rate to {approx}12 SNe/month in 2003.

  17. Pair production of helicity-flipped neutrinos in supernovae

    NASA Technical Reports Server (NTRS)

    Perez, Armando; Gandhi, Raj

    1989-01-01

    The emissivity was calculated for the pair production of helicity-flipped neutrinos, in a way that can be used in supernova calculations. Also presented are simple estimates which show that such process can act as an efficient energy-loss mechanism in the shocked supernova core, and this fact is used to extract neutrino mass limits from SN 1987A neutrino observations.

  18. Type IA Supernovae

    NASA Technical Reports Server (NTRS)

    Wheeler, J. Craig

    1992-01-01

    Spectral calculations show that a model based on the thermonuclear explosion of a degenerate carbon/oxygen white dwarf provides excellent agreement with observations of Type Ia supernovae. Identification of suitable evolutionary progenitors remains a severe problem. General problems with estimation of supernova rates are outlined and the origin of Type Ia supernovae from double degenerate systems are discussed in the context of new rates of explosion per H band luminosity, the lack of observed candidates, and the likely presence of H in the vicinity of some SN Ia events. Re-examination of the problems of triggering Type Ia by accretion of hydrogen from a companion shows that there may be an avenue involving cataclysmic variables, especially if extreme hibernation occurs. Novae may channel accreting white dwarfs to a unique locus in accretion rate/mass space. Systems that undergo secular evolution to higher mass transfer rates could lead to just the conditions necessary for a Type Ia explosion. Tests involving fluorescence or absorption in a surrounding circumstellar medium and the detection of hydrogen stripped from a companion, which should appear at low velocity inside the white dwarf ejecta, are suggested. Possible observational confirmation of the former is described.

  19. Moderately luminous Type II supernovae

    NASA Astrophysics Data System (ADS)

    Inserra, C.; Pastorello, A.; Turatto, M.; Pumo, M. L.; Benetti, S.; Cappellaro, E.; Botticella, M. T.; Bufano, F.; Elias-Rosa, N.; Harutyunyan, A.; Taubenberger, S.; Valenti, S.; Zampieri, L.

    2013-07-01

    Context. Core-collapse Supernovae (CC-SNe) descend from progenitors more massive than about 8 M⊙. Because of the young age of the progenitors, the ejecta may eventually interact with the circumstellar medium (CSM) via highly energetic processes detectable in the radio, X-ray, ultraviolet (UV) and, sometimes, in the optical domains. Aims: In this paper we present ultraviolet, optical and near infrared observations of five Type II SNe, namely SNe 2009dd, 2007pk, 2010aj, 1995ad, and 1996W. Together with few other SNe they form a group of moderately luminous Type II events. We investigate the photometric similarities and differences among these bright objects. We also attempt to characterise them by analysing the spectral evolutions, in order to find some traces of CSM-ejecta interaction. Methods: We collected photometry and spectroscopy with several telescopes in order to construct well-sampled light curves and spectral evolutions from the photospheric to the nebular phases. Both photometry and spectroscopy indicate a degree of heterogeneity in this sample. Modelling the data of SNe 2009dd, 2010aj and 1995ad allows us to constrain the explosion parameters and the properties of the progenitor stars. Results: The light curves have luminous peak magnitudes (-16.95 < MB < -18.70). The ejected masses of 56Ni for three SNe span a wide range of values (2.8 × 10-2 M⊙ < M(56Ni)< 1.4 × 10-1 M⊙), while for a fourth (SN 2010aj) we could determine a stringent upper limit (7 × 10-3 M⊙). Clues of interaction, such as the presence of high velocity (HV) features of the Balmer lines, are visible in the photospheric spectra of SNe 2009dd and 1996W. For SN 2007pk we observe a spectral transition from a Type IIn to a standard Type II SN. Modelling the observations of SNe 2009dd, 2010aj and 1995ad with radiation hydrodynamics codes, we infer kinetic plus thermal energies of about 0.2-0.5 foe, initial radii of 2-5 × 1013 cm and ejected masses of ~5.0-9.5 M⊙. Conclusions: These

  20. Echoes of Historical Supernovae in the Milky Way Galaxy

    NASA Astrophysics Data System (ADS)

    Rest, Armin; Badenes, Carles; Blondin, Stephane; Challis, Peter; Clocchiatti, Alejandro; Filippenko, Alex; Foley, Ryan; Huber, Mark E.; Matheson, Thomas; Mazzali, Paolo; Olsen, Knut; Sauer, Daniel; Sinnott, Brendan; Smith, R. Chris; Suntzeff, Nicholas; Welch, Doug; Bergmann, Marcel

    2010-08-01

    We propose to discover the first light echoes (LEs) associated with the historical Galactic supernovae SN 1181 (3C 58) and SN 1054 (Crab), and to locate additional LE complexes from SN 1680 (Cas A) and SN 1572 (Tycho). Using other facilities, we will obtain spectra of the LEs to determine the nature and properties of these important events. This is a continuation of a previously approved NOAO program to obtain images of regions of significant dust concentration near these Galactic supernova remnants. With data from previous semesters, we found LEs from the Cas A and Tycho supernovae teRest08b. We then used the rich set of LEs from Cas A to examine the Cas A SN from different viewing angles teRest10_casaspec, Rest10_leprofile, finding that in one direction the He I (lambda) 5876 and H(alpha) features are blue-shifted by an additional about 4000 km/s relative to the other directions teRest10_casaspec, which is direct evidence that the SN was asymmetric. The study of scattered-light echoes from Galactic supernovae provides a host of newly-recognized observational benefits which have only just begun to be exploited including (1) a direct comparison of a supernova and its remnant, (2) a three-dimensional view of a supernova, and (3) a Galactic network of absolute distance differences.

  1. Supernovae as sources of interstellar diamonds

    NASA Technical Reports Server (NTRS)

    Nuth, Joseph A., III; Allen, John E., Jr.

    1992-01-01

    Small hydrocarbon grains in the vicinity of a supernova could be annealed by the absorption of several far-ultraviolet photons to produce the tiny diamonds found in meteorites. These freshly-synthesized diamond grains would be bombarded by the heavy ions and neutrals in the supernovae outflow and would thereby acquire the distinctive noble-gas isotopic signature by which they were first isolated. Only diamonds formed relatively close to supernovae would acquire such a signature, since grains formed farther out would be subjected to a much diluted and less energetic plasma environment.

  2. Modeling Type IIn Supernova Light Curves

    NASA Astrophysics Data System (ADS)

    De La Rosa, Janie; Roming, Peter; Fryer, Chris

    2016-01-01

    We present near-by Type IIn supernovae observed with Swift's Ultraviolet/Optical Telescope (UVOT). Based on the diversity of optical light curve properties, this Type II subclass is commonly referred to as heterogeneous. At the time of discovery, our IIn sample is ~ 2 magnitudes brighter at ultraviolet wavelengths than at optical wavelengths, and ultraviolet brightness decays faster than the optical brightness. We use a semi-analytical supernova (SN) model to better understand our IIn observations, and focus on matching specific observed light curves features, i.e peak luminosity and decay rate. The SN models are used to study the effects of initial SN conditions on early light curves, and to show the extent of the "uniqueness" problem in SN light curves. We gratefully acknowledge the contributions from members of the Swift UVOT team, the NASA astrophysics archival data analysis program, and the NASA Swift guest investigator program.

  3. THE SUBLUMINOUS SUPERNOVA 2007qd: A MISSING LINK IN A FAMILY OF LOW-LUMINOSITY TYPE Ia SUPERNOVAE

    SciTech Connect

    McClelland, Colin M.; Garnavich, Peter M.; Galbany, LluIs; Miquel, Ramon; Foley, Ryan J.; Filippenko, Alexei V.; Bassett, Bruce; Wheeler, J. Craig; Goobar, Ariel; Jha, Saurabh W.; Sako, Masao; Frieman, Joshua A.; Sollerman, Jesper; Vinko, Jozsef; Schneider, Donald P.

    2010-09-01

    We present multi-band photometry and multi-epoch spectroscopy of the peculiar Type Ia supernova (SN Ia) 2007qd, discovered by the SDSS-II Supernova Survey. It possesses physical properties intermediate to those of the peculiar SN 2002cx and the extremely low-luminosity SN 2008ha. Optical photometry indicates that it had an extraordinarily fast rise time of {approx}<10 days and a peak absolute B magnitude of -15.4 {+-} 0.2 at most, making it one of the most subluminous SN Ia ever observed. Follow-up spectroscopy of SN 2007qd near maximum brightness unambiguously shows the presence of intermediate-mass elements which are likely caused by carbon/oxygen nuclear burning. Near maximum brightness, SN 2007qd had a photospheric velocity of only 2800 km s{sup -1}, similar to that of SN 2008ha but about 4000 and 7000 km s{sup -1} less than that of SN 2002cx and normal SN Ia, respectively. We show that the peak luminosities of SN 2002cx like objects are highly correlated with both their light-curve stretch and photospheric velocities. Its strong apparent connection to other SN 2002cx like events suggests that SN 2007qd is also a pure deflagration of a white dwarf, although other mechanisms cannot be ruled out. It may be a critical link between SN 2008ha and the other members of the SN 2002cx like class of objects.

  4. Metallicity Gradients of Stripped Core-Collapse Supernovae Host Galaxies

    NASA Astrophysics Data System (ADS)

    Fierroz, David F.; Modjaz, M.

    2013-01-01

    We examine a sample of over 30 galaxies that have hosted stripped core-collapse supernovae including SN IIb, SN Ib, SN Ic and SN Ic with broad lines (SN Ic-BL). The supernovae were discovered by both targeted and untargeted surveys including the Katzman Automatic Imaging Telescope (KAIT), the Nearby Supernova Factory (SNF) and the Palomar Transient Factory (PTF). The metallicity of the supernova environment is expected to play an important role during the short lifetimes of the massive stellar progenitors and likely influences the class of the explosion. We obtain spectra to measure metallicity at the nucleus of the galaxy as well as at HII regions going out to radii that include the supernova site. We use three different oxygen-abundance scales to calibrate and compare metallicities across core-collapse classes. By interpolating the metallicity across the host galaxy we construct our own metallicity gradients that can include SN that have no HII regions at their position and remove the selection effect in place by prior studies. This new feature allows us to probe SN environmental metallicities, even at sites that don’t have recent star formation activity.

  5. Supernova 2010ev: A reddened high velocity gradient type Ia supernova

    NASA Astrophysics Data System (ADS)

    Gutiérrez, Claudia P.; González-Gaitán, Santiago; Folatelli, Gastón; Pignata, Giuliano; Anderson, Joseph P.; Hamuy, Mario; Morrell, Nidia; Stritzinger, Maximilian; Taubenberger, Stefan; Bufano, Filomena; Olivares E., Felipe; Haislip, Joshua B.; Reichart, Daniel E.

    2016-05-01

    Aims: We present and study the spectroscopic and photometric evolution of the type Ia supernova (SN Ia) 2010ev. Methods: We obtain and analyze multiband optical light curves and optical/near-infrared spectroscopy at low and medium resolution spanning -7 days to +300 days from the B-band maximum. Results: A photometric analysis shows that SN 2010ev is a SN Ia of normal brightness with a light-curve shape of Δm15(B) = 1.12 ± 0.02 and a stretch s = 0.94 ± 0.01 suffering significant reddening. From photometric and spectroscopic analysis, we deduce a color excess of E(B - V) = 0.25 ± 0.05 and a reddening law of Rv = 1.54 ± 0.65. Spectroscopically, SN 2010ev belongs to the broad-line SN Ia group, showing stronger than average Si iiλ6355 absorption features. We also find that SN 2010ev is a high velocity gradient SN with v˙Si = 164 ± 7 km s-1 d-1. The photometric and spectral comparison with other supernovae shows that SN 2010ev has similar colors and velocities to SN 2002bo and SN 2002dj. The analysis of the nebular spectra indicates that the [Fe ii]λ7155 and [Ni ii]λ7378 lines are redshifted, as expected for a high velocity gradient supernova. All these common intrinsic and extrinsic properties of the high velocity gradient (HVG) group are different from the low velocity gradient (LVG) normal SN Ia population and suggest significant variety in SN Ia explosions. This paper includes data gathered with the Du Pont Telescope at Las Campanas Observatory, Chile; and the Gemini Observatory, Cerro Pachon, Chile (Gemini Program GS-2010A-Q-14). Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile (ESO Programme 085.D-0577).

  6. Supernova 2010ev: A reddened high velocity gradient type Ia supernova

    NASA Astrophysics Data System (ADS)

    Gutiérrez, Claudia P.; González-Gaitán, Santiago; Folatelli, Gastón; Pignata, Giuliano; Anderson, Joseph P.; Hamuy, Mario; Morrell, Nidia; Stritzinger, Maximilian; Taubenberger, Stefan; Bufano, Filomena; Olivares E., Felipe; Haislip, Joshua B.; Reichart, Daniel E.

    2016-04-01

    Aims: We present and study the spectroscopic and photometric evolution of the type Ia supernova (SN Ia) 2010ev. Methods: We obtain and analyze multiband optical light curves and optical/near-infrared spectroscopy at low and medium resolution spanning -7 days to +300 days from the B-band maximum. Results: A photometric analysis shows that SN 2010ev is a SN Ia of normal brightness with a light-curve shape of Δm15(B) = 1.12 ± 0.02 and a stretch s = 0.94 ± 0.01 suffering significant reddening. From photometric and spectroscopic analysis, we deduce a color excess of E(B - V) = 0.25 ± 0.05 and a reddening law of Rv = 1.54 ± 0.65. Spectroscopically, SN 2010ev belongs to the broad-line SN Ia group, showing stronger than average Si iiλ6355 absorption features. We also find that SN 2010ev is a high velocity gradient SN with v˙Si = 164 ± 7 km s-1 d-1. The photometric and spectral comparison with other supernovae shows that SN 2010ev has similar colors and velocities to SN 2002bo and SN 2002dj. The analysis of the nebular spectra indicates that the [Fe ii]λ7155 and [Ni ii]λ7378 lines are redshifted, as expected for a high velocity gradient supernova. All these common intrinsic and extrinsic properties of the high velocity gradient (HVG) group are different from the low velocity gradient (LVG) normal SN Ia population and suggest significant variety in SN Ia explosions. This paper includes data gathered with the Du Pont Telescope at Las Campanas Observatory, Chile; and the Gemini Observatory, Cerro Pachon, Chile (Gemini Program GS-2010A-Q-14). Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile (ESO Programme 085.D-0577).

  7. The Energetic Universe: a Nobel Surprise

    NASA Astrophysics Data System (ADS)

    Kirshner, Robert P.

    2015-01-01

    he history of cosmic expansion can be accurately traced using Type Ia supernovae (SN Ia) as standard candles. Over the past 40 years, this effort has improved its precision and extended its reach in redshift. Recently, the distances to SN Ia have been measured to a precision of ~5% using luminosity information that is encoded in the shape of the supernova's rest frame optical light curve. By combining observations of supernova distances as measured from their light curves and redshifts measured from spectra, we can detect changes in the cosmic expansion rate. This empirical approach was successfully exploited by the High-Z Supernova Team and by the Supernova Cosmology Project to detect cosmic expansion and to infer the presence of dark energy. The 2011 Nobel Prize in Physics was awarded to Perlmutter, Schmidt and Riess for this discovery. The world's sample of well-observed SN Ia light curves at high redshift and low, approaching 1000 objects, is now large enough to make statistical errors due to sample size a thing of the past. Systematic errors are now the challenge. To learn the properties of dark energy and determine, for example, whether it has an equation-of-state that is different from the cosmological constant demands higher precision and better accuracy. The largest systematic uncertainties come from light curve fitters, photometric calibration errors, and from uncertain knowledge of the scattering properties of dust along the line of sight. Efforts to use SN Ia spectra as luminosity indicators have had some success, but have not yet produced a big step forward. Fortunately, observations of SN Ia in the near infrared (NIR), from 1 to 2 microns, offer a very promising path to better knowledge of the Hubble constant and to improved constraints on dark energy. In the NIR, SN Ia are better standard candles and the effects of dust absorption are smaller. We have begun an HST program dubbed RAISIN (SN IA in the IR) to tighten our grip on dark energy properties

  8. Optical and Ultraviolet Observations of a Low-velocity Type II Plateau Supernova 2013am in M65

    NASA Astrophysics Data System (ADS)

    Zhang, Jujia; Wang, Xiaofeng; Mazzali, Paolo A.; Bai, Jinming; Zhang, Tianmeng; Bersier, David; Huang, Fang; Fan, Yufeng; Mo, Jun; Wang, Jianguo; Yi, Weimin; Wang, Chuanjun; Xin, Yuxin; Liangchang; Zhang, Xiliang; Lun, Baoli; Wang, Xueli; He, Shousheng; Walker, Emma S.

    2014-12-01

    Optical and ultraviolet observations for the nearby type II plateau supernova (SN IIP) 2013am in the nearby spiral galaxy M65 are presented in this paper. The early spectra are characterized by relatively narrow P-Cygni features, with ejecta velocities much lower than observed in normal SNe IIP (i.e., ~2000 km s-1 versus ~5000 km -1 in the middle of the plateau phase). Moreover, prominent Ca II absorptions are also detected in SN 2013am at relatively early phases. These spectral features are reminiscent of those seen in the low-velocity and low-luminosity SN IIP 2005cs. However, SN 2013am exhibits different photometric properties, having shorter plateau phases and brighter light curve tails if compared to SN 2005cs. Adopting RV = 3.1 and a mean value of total reddening derived from the photometric and spectroscopic methods (i.e., E(B - V) = 0.55 ± 0.19 mag), we find that SN 2013am may have reached an absolute V-band peak magnitude of -15.83 ± 0.71 mag and produced an 56Ni mass of 0.016+0.010-0.006 M ⊙ in the explosion. These parameters are close to those derived for SN 2008in and SN 2009N, which have been regarded as "gap-filler" objects linking the faint SNe IIP to the normal ones. This indicates that some low-velocity SNe IIP may not necessarily result from the low-energetic explosions. The low expansion velocities could be due to a lower metallicity of the progenitor stars, a larger envelope mass ejected in the explosion, or the effect of viewing angle where these SNe were observed at an angle away from the polar direction.

  9. Optical and ultraviolet observations of a low-velocity type II plateau supernova 2013am in M65

    SciTech Connect

    Zhang, Jujia; Bai, Jinming; Fan, Yufeng; Wang, Jianguo; Yi, Weimin; Wang, Chuanjun; Xin, Yuxin; Liangchang; Zhang, Xiliang; Lun, Baoli; Wang, Xueli; He, Shousheng; Wang, Xiaofeng; Huang, Fang; Mo, Jun; Mazzali, Paolo A.; Bersier, David; Zhang, Tianmeng; Walker, Emma S. E-mail: baijinming@ynao.ac.cn

    2014-12-10

    Optical and ultraviolet observations for the nearby type II plateau supernova (SN IIP) 2013am in the nearby spiral galaxy M65 are presented in this paper. The early spectra are characterized by relatively narrow P-Cygni features, with ejecta velocities much lower than observed in normal SNe IIP (i.e., ∼2000 km s{sup –1} versus ∼5000 km {sup –1} in the middle of the plateau phase). Moreover, prominent Ca II absorptions are also detected in SN 2013am at relatively early phases. These spectral features are reminiscent of those seen in the low-velocity and low-luminosity SN IIP 2005cs. However, SN 2013am exhibits different photometric properties, having shorter plateau phases and brighter light curve tails if compared to SN 2005cs. Adopting R{sub V} = 3.1 and a mean value of total reddening derived from the photometric and spectroscopic methods (i.e., E(B – V) = 0.55 ± 0.19 mag), we find that SN 2013am may have reached an absolute V-band peak magnitude of –15.83 ± 0.71 mag and produced an {sup 56}Ni mass of 0.016{sub −0.006}{sup +0.010} M {sub ☉} in the explosion. These parameters are close to those derived for SN 2008in and SN 2009N, which have been regarded as 'gap-filler' objects linking the faint SNe IIP to the normal ones. This indicates that some low-velocity SNe IIP may not necessarily result from the low-energetic explosions. The low expansion velocities could be due to a lower metallicity of the progenitor stars, a larger envelope mass ejected in the explosion, or the effect of viewing angle where these SNe were observed at an angle away from the polar direction.

  10. SN X-ray Progenitor?

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Identifying stars that explode, right before they explode, is a tricky proposition since the end of starlife comes swiftly: in thermonuclear deflagrations, in nuclear exhaustion, or maybe in a rapid swirling merger of two dead stellar cores. On the right in the image above is an image of the galaxy NGC 1404 taken by the UV/optical Telescope (UVOT) on the Swift observatory. The circle surrounds SN 2007on, a supernova of Type Ia produced by the explosion of a white dwarf star in a binary system. These types of supernovae are important since they are believed to be 'standard candles', events which have the same intrinsic brightness which can serve as an important yardstick to measure cosmic distances. On the left is an image of the same galaxy taken by the Chandra X-ray observatory four years before the supernova. Conspicuous in the SN source circle is a bright source in the Chandra image, believed to be emission from a compact object+normal star companion: a similar system to the supposed precursor of SN 2007on. If true this would be the first time a Type Ia supernova precursor has ever been seen. But astronomers are still debating whether the Chandra source really is the precursor or not; it seems there's a slight but significant difference in the location of the Chandra source and the supernova. Stay tuned for more developments.

  11. Echoes from Ancient supernovae in the Large Magellanic Cloud

    SciTech Connect

    Rest, A; Suntzeff, N B; Olsen, K; Prieto, J L; Smith, R C; Welch, D L; Becker, A; Bergmann, M; Clocchiatti, A; Cook, K; Garg, A; Huber, M; Miknaitis, G; Minniti, D; Nikolaev, S; Stubbs, C

    2005-06-15

    In principle, historical supernovae could still be visible as scattered-light echoes even centuries later [1, 2]. Searches for surface brightness variations using photographic plates have not recovered any echoes in the regions of historical Galactic supernovae [3]. Using differenced images, our SuperMACHO collaboration has discovered three faint new variable surface brightness complexes with high apparent proper motion pointing back to well-defined positions in the Large Magellanic Cloud (LMC). These correspond to three of the six smallest (and likely youngest) supernova remnants believed to be due to thermonuclear (Type Ia) supernovae [4]. A lower limit to the age of these remnants and echoes is 200 years given the lack of any reported LMC supernovae until 1987. The discovery of historical supernova echoes in the LMC suggests that similar echoes for Galactic supernovae such as Tycho, Kepler, Cas A, or SN1006 could be visible using standard image differencing techniques.

  12. The supernova-gamma-ray burst-jet connection.

    PubMed

    Hjorth, Jens

    2013-06-13

    The observed association between supernovae and gamma-ray bursts represents a cornerstone in our understanding of the nature of gamma-ray bursts. The collapsar model provides a theoretical framework for this connection. A key element is the launch of a bipolar jet (seen as a gamma-ray burst). The resulting hot cocoon disrupts the star, whereas the (56)Ni produced gives rise to radioactive heating of the ejecta, seen as a supernova. In this discussion paper, I summarize the observational status of the supernova-gamma-ray burst connection in the context of the 'engine' picture of jet-driven supernovae and highlight SN 2012bz/GRB 120422A--with its luminous supernova but intermediate high-energy luminosity--as a possible transition object between low-luminosity and jet gamma-ray bursts. The jet channel for supernova explosions may provide new insights into supernova explosions in general. PMID:23630379

  13. Testing the Standardizability of Type Ia Supernovae with the Cepheid Distance of a Twin Supernova

    NASA Astrophysics Data System (ADS)

    Foley, Ryan

    2014-10-01

    Having nearly identical optical light-curve shapes, colors, and spectra, SN 2011by and 2011fe are "twin" Type Ia supernovae (SN Ia). As such, these "standardizable candles" should have identical luminosities. But using independent distance measurements to these SN, their peak luminosity differs by 0.6 mag --- significantly larger than the typical scatter amongst all SN Ia. Differences in their UV spectra indicate that the SN have different metallicities, which could account for the luminosity difference. On the other hand, the distance to SN 2011by, from a Tully-Fisher measurement, may be wrong. We propose to measure a Cepheid distance to SN 2011by to determine if metallicity or an imprecise measurement is causing this large difference.The implications are far reaching for SN cosmology. If the current distance is correct, changing progenitor metallicity could cause large distance biases with redshift. If the distance is revised to bring SN 2011by in line with SN 2011fe, we will infer that metallicity differences are not a large bias for SN cosmology.In the latter case, these data will also provide an additional SN with which we can measure the Hubble constant. Since the number of SN calibrators (only 8 published) limits the precision of our measurement of the Hubble constant, these observations can have a large impact on this measurement.

  14. Supernova explosions in the Universe.

    PubMed

    Burrows, A

    2000-02-17

    During the lifetime of our Milky Way galaxy, there have been something like 100 million supernova explosions, which have enriched the Galaxy with the oxygen we breathe, the iron in our cars, the calcium in our bones and the silicon in the rocks beneath our feet. These exploding stars also influence the birth of new stars and are the source of the energetic cosmic rays that irradiate us on the Earth. The prodigious amount of energy (approximately 10(51), or approximately 2.5 x 10(28) megatonnes of TNT equivalent) and momentum associated with each supernova may even have helped to shape galaxies as they formed in the early Universe. Supernovae are now being used to measure the geometry of the Universe, and have recently been implicated in the decades-old mystery of the origin of the gamma-ray bursts. Together with major conceptual advances in our theoretical understanding of supernovae, these developments have made supernovae the centre of attention in astrophysics. PMID:10693794

  15. Supernovae and Gamma-Ray Bursts

    NASA Astrophysics Data System (ADS)

    Livio, Mario; Panagia, Nino; Sahu, Kailash

    2001-07-01

    Participants; Preface; Gamma-ray burst-supernova relation B. Paczynski; Observations of gamma-ray bursts G. Fishman; Fireballs T. Piran; Gamma-ray mechanisms M. Rees; Prompt optical emission from gamma-ray bursts R. Kehoe, C. Akerlof, R. Balsano, S. Barthelmy, J. Bloch, P. Butterworth, D. Casperson, T. Cline, S. Fletcher, F. Frontera, G. Gisler, J. Heise, J. Hills, K. Hurley, B. Lee, S. Marshall, T. McKay, A. Pawl, L. Piro, B. Priedhorsky, J. Szymanski and J. Wren; X-ray afterglows of gamma-ray bursts L. Piro; The first year of optical-IR observations of SN1998bw I. Danziger, T. Augusteijn, J. Brewer, E. Cappellaro, V. Doublier, T. Galama, J. Gonzalez, O. Hainaut, B. Leibundgut, C. Lidman, P. Mazzali, K. Nomoto, F. Patat, J. Spyromilio, M. Turatto, J. Van Paradijs, P. Vreeswijk and J. Walsh; X-ray emission of Supernova 1998bw in the error box of GRB980425 E. Pian; Direct analysis of spectra of type Ic supernovae D. Branch; The interaction of supernovae and gamma-ray bursts with their surroundings R. Chevalier; Magnetars, soft gamma-ray repeaters and gamma-ray bursts A. Harding; Super-luminous supernova remnants Y. -H. Chu, C. -H. Chen and S. -P. Lai; The properties of hypernovae: SNe Ic 1998bw, 1997ef, and SN IIn 1997cy K. Nomoto, P. Mazzali, T. Nakamura, K. Iwanmoto, K. Maeda, T. Suzuki, M. Turatto, I. Danziger and F. Patat; Collapsars, Gamma-Ray Bursts, and Supernovae S. Woosley, A. MacFadyen and A. Heger; Pre-supernova evolution of massive stars N. Panagia and G. Bono; Radio supernovae and GRB 980425 K. Weiler, N. Panagia, R. Sramek, S. Van Dyk, M. Montes and C. Lacey; Models for Ia supernovae and evolutionary effects P. Hoflich and I. Dominguez; Deflagration to detonation A. Khokhlov; Universality in SN Iae and the Phillips relation D. Arnett; Abundances from supernovae F. -K. Thielemann, F. Brachwitz, C. Freiburghaus, S. Rosswog, K. Iwamoto, T. Nakamura, K. Nomoto, H. Umeda, K. Langanke, G. Martinez-Pinedo, D. Dean, W. Hix and M. Strayer; Sne, GRBs, and the

  16. Observations of Type Iax Supernovae

    NASA Astrophysics Data System (ADS)

    McCully, Curtis; Jha, S.; Foley, R. J.

    2014-01-01

    Type Iax supernovae (SNe Iax) are a class of peculiar cousins to normal Type Ia SNe, with SN 2002cx as the prototype. These explosions have photospheric velocities half those of normal SNe Ia, but are otherwise spectroscopically similar at early times. SNe Iax are typically more than ~1 magnitude fainter than normal SNe Ia with similar light curve shapes. These objects depart most dramatically from normal SNe Ia at late epochs, with a slow photometric decline and spectra that are unmatched by any other kind of supernova. I will present Hubble Space Telescope and ground-based optical and near-infrared observations of SN 2005hk and SN 2008A, typical SNe Iax, emphasizing results from late-time data. I will also show new UV observations of the type Iax SN 2013dh, and discuss constraints on the progenitor systems of these peculiar SNe. Recent models of a deflagration explosion in a carbon/oxygen white dwarf that does not completely disrupt the star can match some of the observed properties of SNe Iax, but no published model is consistent with all of the observations.

  17. Runaway Stars in Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Pannicke, Anna; Neuhaeuser, Ralph; Dinçel, Baha

    2016-07-01

    Half of all stars and in particular 70 % of the massive stars are a part of a multiple system. A possible development for the system after the core collapse supernova (SN) of the more massive component is as follows: The binary is disrupted by the SN. The formed neutron star is ejected by the SN kick whereas the companion star either remains within the system and is gravitationally bounded to the neutron star, or is ejected with a spatial velocity comparable to its former orbital velocity (up to 500 km/s). Such stars with a large peculiar space velocity are called runaway stars. We present our observational results of the supernova remnants (SNRs) G184.6-5.8, G74.0-8.5 and G119.5+10.2. The focus of this project lies on the detection of low mass runaway stars. We analyze the spectra of a number of candidates and discuss their possibility of being the former companions of the SN progenitor stars. The spectra were obtained with INT in Tenerife, Calar Alto Astronomical Observatory and the University Observatory Jena. Also we investigate the field stars in the neighborhood of the SNRs G74.0-8.5 and G119.5+10.2 and calculate more precise distances for these SNRs.

  18. Observing the next galactic supernova

    SciTech Connect

    Adams, Scott M.; Kochanek, C. S.; Beacom, John F.; Stanek, K. Z.; Vagins, Mark R.

    2013-12-01

    No supernova (SN) in the Milky Way has been observed since the invention of the optical telescope, instruments for other wavelengths, neutrino detectors, or gravitational wave observatories. It would be a tragedy to miss the opportunity to fully characterize the next one. To aid preparations for its observations, we model the distance, extinction, and magnitude probability distributions of a successful Galactic core-collapse supernova (ccSN), its shock breakout radiation, and its massive star progenitor. We find, at very high probability (≅ 100%), that the next Galactic SN will easily be detectable in the near-IR and that near-IR photometry of the progenitor star very likely (≅ 92%) already exists in the Two Micron All Sky Survey. Most ccSNe (98%) will be easily observed in the optical, but a significant fraction (43%) will lack observations of the progenitor due to a combination of survey sensitivity and confusion. If neutrino detection experiments can quickly disseminate a likely position (∼3°), we show that a modestly priced IR camera system can probably detect the shock breakout radiation pulse even in daytime (64% for the cheapest design). Neutrino experiments should seriously consider adding such systems, both for their scientific return and as an added and internal layer of protection against false triggers. We find that shock breakouts from failed ccSNe of red supergiants may be more observable than those of successful SNe due to their lower radiation temperatures. We review the process by which neutrinos from a Galactic ccSN would be detected and announced. We provide new information on the EGADS system and its potential for providing instant neutrino alerts. We also discuss the distance, extinction, and magnitude probability distributions for the next Galactic Type Ia supernova (SN Ia). Based on our modeled observability, we find a Galactic ccSN rate of 3.2{sub −2.6}{sup +7.3} per century and a Galactic SN Ia rate of 1.4{sub −0.8}{sup +1.4} per

  19. Radio Emission from Supernovae

    NASA Astrophysics Data System (ADS)

    Weiler, Kurt W.; Panagia, Nino; Sramek, Richard A.; van Dyk, Schuyler D.; Williams, Christopher L.; Stockdale, Christopher J.; Kelley, Matthew T.

    2007-10-01

    Study of radio supernovae over the past 27 years includes more than three dozen detected objects and more than 150 upper limits. From this work it is possible to identify classes of radio properties, demonstrate conformance to and deviations from existing models, estimate the density and structure of the circumstellar material and, by inference, the evolution of the presupernova stellar wind, and reveal the last stages of stellar evolution before explosion. It is also possible to detect ionized hydrogen along the line of sight, to demonstrate binary properties of the presupernova stellar system, and to detect clumpiness of the circumstellar material. Along with reviewing these general properties of the radio emission from supernovae, we present our extensive observations of the radio emission from supernova (SN) 1993J in M 81 (NGC 3031) made with the Very Large Array and other radio telescopes. The SN 1993J radio emission evolves regularly in both time and frequency, and the usual interpretation in terms of shock interaction with a circumstellar medium (CSM) formed by a pre-supernova stellar wind describes the observations rather well considering the complexity of the phenomenon. However: 1) The highest frequency measurements at 85-110 GHz at early times (<40 days) are not well fitted by the parameterization which describes the cm wavelength measurements rather well. 2) At mid-cm wavelengths there is often deviation from the fitted radio light curves, particularly near the peak flux density, and considerable shorter term deviations in the declining portion when the emission has become optically thin. 3) At a time ~3100 days after shock breakout, the decline rate of the radio emission steepens from (t+β)β~-0.7 to β~-2.7 without change in the spectral index (ν+αα~-0.81). However, this decline is best described not as a power-law, but as an exponential decay starting at day ~3100 with an e-folding time of ~1100 days. 4) The best overall fit to all of the data is

  20. Gamma-ray constraints on supernova nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Leising, Mark D.

    1994-01-01

    Gamma-ray spectroscopy holds great promise for probing nucleosynthesis in individual supernova explosions via short-lived radioactivity, and for measuring current global Galactic supernova nucleosynthesis with longer-lived radioactivity. It was somewhat surprising that the former case was realized first for a Type II supernova, when both Co-56 and Co-57 were detected in SN 1987A. These provide unprecedented constraints on models of Type II explosions and nucleosynthesis. Live Al-26 in the Galaxy might come from Type II supernovae, and if it is eventually shown to be so, can constrain massive star evolution, supernova nucleosynthesis, and the Galactic Type II supernova rate. Type Ia supernovae, thought to be thermonuclear explosions, have not yet been detected in gamma-rays. This is somewhat surprising given current models and recent Co-56 detection attempts. Ultimately, gamma-ray measurements can confirm their thermonuclear nature, probe the nuclear burning conditions, and help evaluate their contributions to Galactic nucleosynthesis. Type Ib/c supernovae are poorly understood. Whether they are core collapse or thermonuclear events might be ultimately settled by gamma-ray observations. Depending on details of the nuclear processing, any of these supernova types might contribute to a detectable diffuse glow of Fe-60 gamma-ray lines. Previous attempts at detection have come very close to expected emission levels. Remnants of any type of age less that a few centuries might be detectable as individual spots of Ti-44 gamma-ray line emission. It is in fact quite surprising that previous surveys have not discovered such spots, and the constraints on the combination of nucleosynthesis yields and supernova rates are very interesting. All of these interesting limits and possibilities mean that the next mission, International Gamma-Ray Astrophysics Laboratory (INTEGRAL), if it has sufficient sensitivity, is very likely to lead to the realization of much of the great potential

  1. Ionospheric effects of supernova explosions

    NASA Astrophysics Data System (ADS)

    Edwards, P. J.

    Possible ionospheric effects of supernova explosions are considered, with special attention given to those of SN 1987a. Results are presented on the calculations of anticipated X-ray/UV flare parameters, including the shock temperature, the minimum flare duration, the average photon energy, and the shock-front travel time for a range of stellar radii bracketing SK 202-69, which was identified by White Malin (1987) as the progenitor star for SN 1987a. It is shown that the characteristics of the X-ray/UV flare are strongly influenced by the radius of the shock wave breakout, so that the flare from SN 1987a can be anticipated to have characteristics intermediate between those attributed to compact stars and stars with extended envelopes.

  2. The World's Strangest Supernova May Not Be a Supernova At All

    NASA Astrophysics Data System (ADS)

    Moore, C.

    2012-06-01

    (Abstract only) SN 2008ha is the least luminous supernova ever to be observed. It is unclear what caused this obscurity to occur. For the last three years I have been doing independent follow-up research on SN 2008ha. SN 2008ha is believed to be 100 times brighter than a nova, but 1,000 times dimmer then a supernova. The spectrum to some degree was classic Type Ia supernova because of the lack of hydrogen and abundance of silicon, but there are many other factors to be considered. SN 2008ha had a short rise time of only 10 days (typical Type Ia is 19.5 days). It has low expansion velocities of only 2,000km compared to the typical Ia with very small kinetic energy per unit mass of ejecta. Although some elements of the spectrum are consistent with those of a Type Ia, narrow lines were observed. This is just one of several characteristics that SN 2008ha shares with the "SN 2002cx-like class" of supernovae. SN 2008ha is believed to be the most extreme of this sub-class of supernovae with the smallest amount of space between lines, 5 days shorter rise time, being significantly fainter, and having lower velocities. With all these things considered, it does make classification as a Type Ia questionable. In fact it is even questionable if this is a supernova at all, and not just an "imposter." This may have just been a "star burp" which means that the supernova may have failed, resulting in some parts of the star being left, maybe even enough remains to explode again as seen in the case of SN 2006jc. This may have occurred because the explosion was not deep enough in the core of the star, and only eliminating some or all of the hydrogen envelope and leaving behind the carbon and oxygen inner layers, instead resulting in a Type Ic supernova. It would be interesting to see what, if anything is left of the star; this could make it a possible Hubble candidate. The idea that it may "burp" again makes it especially important.

  3. Supernova remnants

    NASA Astrophysics Data System (ADS)

    Decourchelle, A.

    2016-06-01

    Supernova remnants result from the explosion of a star and keep trace, in their young ejecta-dominated phase, both of the explosion mechanism and to a lesser extent of the nature of the progenitor. They inject a large amount of energy into their surroundings, which impacts significantly the interstellar medium and to a larger extent the working of the galaxy by distributing heavy elements, heating to tens of million degrees large fractions of gas, accelerating high-energy particles, generating turbulence and amplification of the magnetic field. I will review the observational results on supernova remnants and their related scientific issues before suggesting directions for future ambitious XMM-Newton observations.

  4. Spectropolarimetry of SN 2011fe

    NASA Astrophysics Data System (ADS)

    Milne, Peter; Williams, G.; Smith, P. S.; Smith, N.

    2014-01-01

    The Supernova Spectropolarimetry Project is a recently formed collaboration between observers and theorists that focuses on decoding the complex, time-dependent spectropolarimetric behavior of supernovae (SNe) of all types. Using the CCD Imaging/Spectropolarimeter (SPOL) at the 61" Kuiper, the 90" Bok, and the 6.5-m MMT telescopes, we obtain multi-epoch observations of each target, aiming to construct the most comprehensive survey to date of supernovae in polarized light. We present spectropolarimetry of SN 2011fe obtained for 8 epochs from August 2011-April 2012. The near-peak spectra show the evolution of the SiIIλ6355Å feature, as well as other polarized line features. The late nebular spectra show the line ratios and line profiles of the forbidden iron-peak elements. The spectral series permit estimation of the interstellar polarization. Collectively, these observations permit a study of the evolution of the emission from a NUV-blue type Ia supernova.

  5. Unparticle constraints from supernova 1987A

    SciTech Connect

    Hannestad, Steen; Raffelt, Georg; Wong, Yvonne Y. Y.

    2007-12-15

    The existence of an unparticle sector, weakly coupled to the standard model, would have a profound impact on supernova (SN) physics. Emission of energy into the unparticle sector from the core of SN 1987A would have significantly shortened the observed neutrino burst. The unparticle interaction with nucleons, neutrinos, electrons and muons is constrained to be so weak that it is unlikely to provide any missing-energy signature at colliders. One important exception are models where scale invariance in the hidden sector is broken by the Higgs vacuum expectation value. In this case the SN emission is suppressed by threshold effects.

  6. Supernova hydrodynamics experiments using the Nova laser

    SciTech Connect

    Remington, B.A.; Glendinning, S.G.; Estabrook, K.; Wallace, R.J.; Rubenchik, A.; Kane, J.; Arnett, D.; Drake, R.P.; McCray, R.

    1997-04-01

    We are developing experiments using the Nova laser to investigate two areas of physics relevant to core-collapse supernovae (SN): (1) compressible nonlinear hydrodynamic mixing and (2) radiative shock hydrodynamics. In the former, we are examining the differences between the 2D and 3D evolution of the Rayleigh-Taylor instability, an issue critical to the observables emerging from SN in the first year after exploding. In the latter, we are investigating the evolution of a colliding plasma system relevant to the ejecta-stellar wind interactions of the early stages of SN remnant formation. The experiments and astrophysical implications are discussed.

  7. Red-Supergiant and Supernova Rate Problems: Implication for the Relic Supernova Neutrino Spectrum

    NASA Astrophysics Data System (ADS)

    Hidaka, J.; Kajino, T.; Mathews, G. J.

    2016-08-01

    Direct observations of core-collapse supernovae (SNe) and their red supergiant (RSG) progenitors suggest that the upper mass limit of RSGs may be only about 16.5{--}18{M}ȯ , while the standard theoretical value is as much as 25{M}ȯ . We investigate the possibility that RSGs with m\\gt 16.5{--}18{M}ȯ end their lives as failed supernovae (fSNe) and analyze their contribution to the relic supernova neutrino spectrum. We show that adopting this mass limit simultaneously solves both the RSG problem and the supernova rate problem. In addition, energetic neutrinos that originated from fSNe are sensitive to the explosion mechanism, and in particular, to the nuclear equation of state (EOS). We show that this solution to the RSG problem might also be used to constrain the EOS for failed supernovae.

  8. VLA radio upper limit on Type IIn Supernova 2007pk

    NASA Astrophysics Data System (ADS)

    Chandra, Poonam; Soderberg, Alicia

    2007-11-01

    Poonam Chandra and Alicia Soderberg report on behalf of a larger collaboration: We observed Type IIn supernova SN 2007pk (CBET 1129) with the VLA in 8.46 GHz band on 2007, November 12.20 UT, 1.89 days since discovery (CBET 1129). We do not detect radio emission from the SN position (CBET 1129). The flux density at the SN position is 11 +/-26 uJy.

  9. Quantitative comparison between type Ia supernova spectra at low and high redshifts: a case study

    NASA Astrophysics Data System (ADS)

    Garavini, G.; Folatelli, G.; Nobili, S.; Aldering, G.; Amanullah, R.; Antilogus, P.; Astier, P.; Blanc, G.; Bronder, T.; Burns, M. S.; Conley, A.; Deustua, S. E.; Doi, M.; Fabbro, S.; Fadeyev, V.; Gibbons, R.; Goldhaber, G.; Goobar, A.; Groom, D. E.; Hook, I.; Howell, D. A.; Kashikawa, N.; Kim, A. G.; Kowalski, M.; Kuznetsova, N.; Lee, B. C.; Lidman, C.; Mendez, J.; Morokuma, T.; Motohara, K.; Nugent, P. E.; Pain, R.; Perlmutter, S.; Quimby, R.; Raux, J.; Regnault, N.; Ruiz-Lapuente, P.; Sainton, G.; Schahmaneche, K.; Smith, E.; Spadafora, A. L.; Stanishev, V.; Thomas, R. C.; Walton, N. A.; Wang, L.; Wood-Vasey, W. M.; Yasuda, N.

    2007-08-01

    We develop a method to measure the strength of the absorption features in type Ia supernova (SN Ia) spectra and use it to make a quantitative comparisons between the spectra of type Ia supernovae at low and high redshifts. In this case study, we apply the method to 12 high-redshift (0.212 ≤ z ≤ 0.912) SNe Ia observed by the Supernova Cosmology Project. Through measurements of the strengths of these features and of the blueshift of the absorption minimum in Ca ii H&K, we show that the spectra of the high-redshift SNe Ia are quantitatively similar to spectra of nearby SNe Ia (z < 0.15). One supernova in our high redshift sample, SN 2002fd at z = 0.279, is found to have spectral characteristics that are associated with peculiar SN 1991T/SN 1999aa-like supernovae.

  10. Quantitative comparison between Type Ia supernova spectra at low and high redshifts: A case study

    SciTech Connect

    Supernova Cosmology Project; Nugent, Peter E; Garavini, G.; Folatelli, G.; Nobili, S.; Aldering, G.; Amanullah, R.; Antilogus, P.; Astier, P.; Blanc, G.; Bronder, J.; Burns, M.S.; Conley, A.; Deustua, S. E.; Doi, M.; Fabbro, S.; Fadeyev, V.; Gibbons, R.; Goldhaber, G.; Goobar, A.; Groom, D. E.; Hook, I.; Howell, D. A.; Kashikawa, N.; Kim, A. G.; Kowalski, M.; Kuznetsova, N.; Lee, B. C.; Lidman, C.; Mendez, J.; Morokuma, T.; Motohara, K.; Nugent, P. E.; Pain, R.; Perlmutter, S.; Quimby, R.; Raux, J.; Regnault, N.; Ruiz-Lapuente, P.; Sainton, G.; Schahmaneche, K.; Smith, E.; Spadafora, A. L.; Stanishev, V.; Thomas, R. C.; Walton, N. A.; Wang, L.; Wood-Vasey, W. M.; Yasuda, N.

    2008-03-24

    We develop a method to measure the strength of the absorption features in type Ia supernova (SN Ia) spectra and use it to make a quantitative comparisons between the spectra of type Ia supernovae at low and high redshifts. In this case study, we apply the method to 12 high-redshift (0.212 = z = 0.912) SNe Ia observed by the Supernova Cosmology Project. Through measurements of the strengths of these features and of the blueshift of theabsorption minimum in Ca ii H&K, we show that the spectra of the high-redshift SNe Ia are quantitatively similar to spectra of nearby SNe Ia (z< 0.15). One supernova in our high redshift sample, SN 2002fd at z = 0.279, is found to have spectral characteristics that are associated with peculiar SN 1991T/SN 1999aa-like supernovae.

  11. Scaling supernova hydrodynamics to the laboratory

    SciTech Connect

    Kane, J.O.

    1999-06-01

    Supernova (SN) 1987A focused attention on the critical role of hydrodynamic instabilities in the evolution of supernovae. To test the modeling of these instabilities, we are developing laboratory experiments of hydrodynamic mixing under conditions relevant to supernovae. Initial results were reported in J. Kane et al., Astrophys. J.478, L75 (1997) The Nova laser is used to shock two-layer targets, producing Richtmyer-Meshkov (RM) and Rayleigh-Taylor (RT) instabilities at the interfaces between the layers, analogous to instabilities seen at the interfaces of SN 1987A. Because the hydrodynamics in the laser experiments at intermediate times (3-40 ns) and in SN 1987A at intermediate times (5 s-10{sup 4} s) are well described by the Euler equations, the hydrodynamics scale between the two regimes. The experiments are modeled using the hydrodynamics codes HYADES and CALE, and the supernova code PROMETHEUS, thus serving as a benchmark for PROMETHEUS. Results of the experiments and simulations are presented. Analysis of the spike and bubble velocities in the experiment using potential flow theory and a modified Ott thin shell theory is presented. A numerical study of 2D vs. 3D differences in instability growth at the O-He and He-H interface of SN 1987A, and the design for analogous laser experiments are presented. We discuss further work to incorporate more features of the SN in the experiments, including spherical geometry, multiple layers and density gradients. Past and ongoing work in laboratory and laser astrophysics is reviewed, including experimental work on supernova remnants (SNRs). A numerical study of RM instability in SNRs is presented.

  12. Astronomical Resources: Supernovae.

    ERIC Educational Resources Information Center

    Fraknoi, Andrew

    1987-01-01

    Contains a partially annotated, nontechnical bibliography of recent materials about supernovae, including some about the discovery of a supernova in the Large Magellanic Cloud. Includes citations of general books and articles about supernovae, articles about Supernova 1987A, and a few science fiction stories using supernovae. (TW)

  13. CORE-COLLAPSE SUPERNOVAE AND HOST GALAXY STELLAR POPULATIONS

    SciTech Connect

    Kelly, Patrick L.; Kirshner, Robert P.

    2012-11-10

    We have used images and spectra of the Sloan Digital Sky Survey to examine the host galaxies of 519 nearby supernovae (SN). The colors at the sites of the explosions, as well as chemical abundances, and specific star formation rates (SFRs) of the host galaxies provide circumstantial evidence on the origin of each SN type. We examine separately SN II, SN IIn, SN IIb, SN Ib, SN Ic, and SN Ic with broad lines (SN Ic-BL). For host galaxies that have multiple spectroscopic fibers, we select the fiber with host radial offset most similar to that of the SN. Type Ic SN explode at small host offsets, and their hosts have exceptionally strongly star-forming, metal-rich, and dusty stellar populations near their centers. The SN Ic-BL and SN IIb explode in exceptionally blue locations, and, in our sample, we find that the host spectra for SN Ic-BL show lower average oxygen abundances than those for SN Ic. SN IIb host fiber spectra are also more metal-poor than those for SN Ib, although a significant difference exists for only one of two strong-line diagnostics. SN Ic-BL host galaxy emission lines show strong central specific SFRs. In contrast, we find no strong evidence for different environments for SN IIn compared to the sites of SN II. Because our SN sample is constructed from a variety of sources, there is always a risk that sampling methods can produce misleading results. We have separated the SN discovered by targeted surveys from those discovered by galaxy-impartial searches to examine these questions and show that our results do not depend sensitively on the discovery technique.

  14. Type Ibn Supernovae: Not a Single Class

    NASA Astrophysics Data System (ADS)

    Hosseinzadeh, Griffin; Arcavi, Iair; Howell, Dale Andrew; McCully, Curtis; Valenti, Stefano

    2016-01-01

    Type Ibn supernovae are a small yet diverse class of explosions whose spectra are characterized by low-velocity helium emission lines. The prevailing theory has been that these are the core-collapse explosions of very massive stars embedded in helium-rich circumstellar material. However, unlike the more common Type IIn supernovae, whose interaction with hydrogen-rich circumstellar material has been shown to generate a wide variety of light curve shapes, we find that light curves of Type Ibn supernovae are more homogeneous and faster evolving. Spectroscopically, we find that Type Ibn supernovae divide cleanly into two classes, only one of which resembles the archetypal Type Ibn SN 2006jc. We explore various photometric and spectroscopic parameter spaces in order to characterize these two classes. We consider the possibility that not all objects classified as Type Ibn have the same physical origin.

  15. Electronic Structure and Defect Physics of Tin Sulfides: SnS, Sn2S3 , and Sn S2

    NASA Astrophysics Data System (ADS)

    Kumagai, Yu; Burton, Lee A.; Walsh, Aron; Oba, Fumiyasu

    2016-07-01

    The tin sulfides SnS, Sn2S3 , and Sn S2 are investigated for a wide variety of applications such as photovoltaics, thermoelectrics, two-dimensional electronic devices, Li ion battery electrodes, and photocatalysts. For these applications, native point defects play important roles, but only those of SnS have been investigated theoretically in the literature. In this study, we consider the band structures, band-edge positions, and thermodynamical stability of the tin sulfides using a density functional that accounts for van der Waals corrections and the G W0 approximation. We revisit the point-defect properties, namely, electronic and atomic structures and energetics of defects, in SnS and newly examine those in Sn S2 and Sn2S3 with a comparison to those in SnS. We find that Sn S2 shows contrasting defect properties to SnS: Undoped SnS shows p -type behavior, whereas Sn S2 shows n type, which are mainly attributed to the tin vacancies and tin interstitials, respectively. We also find that the defect features in Sn2S3 can be described as a combination of those in SnS and Sn S2 , intrinsically Sn2S3 showing n -type behavior. However, the conversion to p type can be attained by doping with a large monovalent cation, namely, potassium. The ambipolar dopability, coupled with the earth abundance of its constituents, indicates great potential for electronic applications, including photovoltaics.

  16. Cosmological and supernova neutrinos

    NASA Astrophysics Data System (ADS)

    Kajino, T.; Aoki, W.; Balantekin, A. B.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Kusakabe, M.; Mathews, G. J.; Nakamura, K.; Pehlivan, Y.; Shibagaki, S.; Suzuki, T.

    2014-06-01

    The Big Bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) anisotropies are the pillars of modern cosmology. It has recently been suggested that axion which is a dark matter candidate in the framework of the standard model could condensate in the early universe and induce photon cooling before the epoch of the photon last scattering. Although this may render a solution to the overproduction problem of primordial 7Li abundance, there arises another serious difficulty of overproducing D abundance. We propose a hybrid dark matter model with both axions and relic supersymmetric (SUSY) particles to solve both overproduction problems of the primordial D and 7Li abundances simultaneously. The BBN also serves to constrain the nature of neutrinos. Considering non-thermal photons produced in the decay of the heavy sterile neutrinos due to the magnetic moment, we explore the cosmological constraint on the strength of neutrino magnetic moment consistent with the observed light element abundances. Core-collapse supernovae eject huge flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like 7Li, 11B, 92Nb, 138La and 180Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. Combining the recent experimental constraints on θ13 with predicted and observed supernova-produced abundance ratio 11B/7Li encapsulated in the presolar grains from the Murchison meteorite, we show a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos (SRN) that may indicate the softness of the equation of state (EoS) of nuclear matter and adiabatic conditions of the neutrino oscillation.

  17. Cosmological and supernova neutrinos

    SciTech Connect

    Kajino, T.; Aoki, W.; Balantekin, A. B.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Shibagaki, S.; Kusakabe, M.; Mathews, G. J.; Nakamura, K.; Pehlivan, Y.; Suzuki, T.

    2014-06-24

    The Big Bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) anisotropies are the pillars of modern cosmology. It has recently been suggested that axion which is a dark matter candidate in the framework of the standard model could condensate in the early universe and induce photon cooling before the epoch of the photon last scattering. Although this may render a solution to the overproduction problem of primordial {sup 7}Li abundance, there arises another serious difficulty of overproducing D abundance. We propose a hybrid dark matter model with both axions and relic supersymmetric (SUSY) particles to solve both overproduction problems of the primordial D and {sup 7}Li abundances simultaneously. The BBN also serves to constrain the nature of neutrinos. Considering non-thermal photons produced in the decay of the heavy sterile neutrinos due to the magnetic moment, we explore the cosmological constraint on the strength of neutrino magnetic moment consistent with the observed light element abundances. Core-collapse supernovae eject huge flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. Combining the recent experimental constraints on θ{sub 13} with predicted and observed supernova-produced abundance ratio {sup 11}B/{sup 7}Li encapsulated in the presolar grains from the Murchison meteorite, we show a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos (SRN) that may indicate the softness of the equation of state (EoS) of nuclear matter and adiabatic conditions of the neutrino oscillation.

  18. On the hydrogen emission from the type Ia supernova 2002ic

    SciTech Connect

    Wang, Lifan; Baade, Dietrich; Hoflich, Peter; Wheeler, J. Craig; Kawabata, Koji; Nomoto, Ken'ichi

    2003-12-10

    The discovery of SN 2002ic by the Supernova Factory and the subsequent spectroscopic studies have led to the surprising finding that SN 2002ic is a type Ia supernova with strong ejecta-circumstellar interaction. Here we show that nearly 1 year after the explosion the supernova has become fainter overall, but the H-alpha emission has brightened and broadened dramatically compared to earlier observations. We have obtained spectropolarimetry data which show that the hydrogen-rich matter is highly aspherically distributed. These observations suggest that the supernova exploded inside a dense, clumpy, disk-like circumstellar environment.

  19. Supernova Feedback and the Hot Gas Filling Fraction of the Interstellar Medium

    NASA Astrophysics Data System (ADS)

    Li, Miao; Ostriker, Jeremiah P.; Cen, Renyue; Bryan, Greg L.; Naab, Thorsten

    2015-11-01

    Supernovae (SNe), the most energetic stellar feedback mechanism, are crucial for regulating the interstellar medium (ISM) and launching galactic winds. We explore how supernova remnants (SNRs) create a multiphase medium by performing three-dimentional hydrodynamical simulations at various SN rates, S, and ISM average densities, \\bar{n}. The evolution of an SNR in a self-consistently generated three-phase ISM is qualitatively different from that in a uniform or a two-phase warm/cold medium. By traveling faster and further in the low-density hot phase, the domain of an SNR increases by >102.5. Varying \\bar{n} and S, we find that a steady state can only be achieved when the hot gas volume fraction {f}{{V,hot}}≲ 0.6+/- 0.1. Above that level, overlapping SNRs render connecting topology of the hot gas, and the ISM is subjected to thermal runaway. Photoelectric heating (PEH) has a surprisingly strong impact on {f}{{V,hot}}. For \\bar{n}≳ 3 {{cm}}-3, a reasonable PEH rate is able to suppress the thermal runaway. Overall, we determine the critical SN rate for the onset of thermal runaway to be {S}{{crit}}=200{(\\bar{n}/1 {{cm}}-3)}k{({E}{{SN}}/{10}51 {{erg}})}-1 {{{kpc}}}-3 {{Myr}}-1, where k = (1.2, 2.7) for \\bar{n}≤slant 1 and \\gt 1 {{cm}}-3, respectively. We present a fitting formula of the ISM pressure P(\\bar{n},S), which can be used as an effective equation of state in cosmological simulations. Despite the five orders of magnitude span of (\\bar{n},S), the average Mach number varies little: {M} ≈ 0.5 ± 0.2, 1.2 ± 0.3, and 2.3 ± 0.9 for the hot, warm, and cold phases, respectively.

  20. Supernova neutrinos and explosive nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Kajino, T.; Aoki, W.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Mathews, G. J.; Nakamura, K.; Shibagaki, S.; Suzuki, T.

    2014-05-01

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos. We studied the explosive nucleosyn-thesis in supernovae and found that several isotopes 7Li, 11B, 92Nb, 138La and 180Ta as well as r-process nuclei are affected by the neutrino interactions. The abundance of these isotopes therefore depends strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We discuss first how to determine the neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the effects of neutrino oscillation on their abundances, and propose a novel method to determine the still unknown neutrino oscillation parameters, mass hierarchy and θ13, simultaneously. There is recent evidence that SiC X grains from the Murchison meteorite may contain supernova-produced light elements 11B and 7Li encapsulated in the presolar grains. Combining the recent experimental constraints on θ13, we show that our method sug-gests at a marginal preference for an inverted neutrino mass hierarchy. Finally, we discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  1. Supernova neutrinos and explosive nucleosynthesis

    SciTech Connect

    Kajino, T.; Aoki, W.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Shibagaki, S.; Mathews, G. J.; Nakamura, K.; Suzuki, T.

    2014-05-09

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos. We studied the explosive nucleosyn-thesis in supernovae and found that several isotopes {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta as well as r-process nuclei are affected by the neutrino interactions. The abundance of these isotopes therefore depends strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We discuss first how to determine the neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the effects of neutrino oscillation on their abundances, and propose a novel method to determine the still unknown neutrino oscillation parameters, mass hierarchy and θ{sub 13}, simultaneously. There is recent evidence that SiC X grains from the Murchison meteorite may contain supernova-produced light elements {sup 11}B and {sup 7}Li encapsulated in the presolar grains. Combining the recent experimental constraints on θ{sub 13}, we show that our method sug-gests at a marginal preference for an inverted neutrino mass hierarchy. Finally, we discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  2. Supernova relic neutrinos and the supernova rate problem: Analysis of uncertainties and detectability of ONeMg and failed supernovae

    SciTech Connect

    Mathews, Grant J.; Hidaka, Jun; Kajino, Toshitaka; Suzuki, Jyutaro

    2014-08-01

    Direct measurements of the core collapse supernova rate (R{sub SN}) in the redshift range 0 ≤ z ≤ 1 appear to be about a factor of two smaller than the rate inferred from the measured cosmic massive star formation rate (SFR). This discrepancy would imply that about one-half of the massive stars that have been born in the local observed comoving volume did not explode as luminous supernovae. In this work, we explore the possibility that one could clarify the source of this 'supernova rate problem' by detecting the energy spectrum of supernova relic neutrinos with a next generation 10{sup 6} ton water Čerenkov detector like Hyper-Kamiokande. First, we re-examine the supernova rate problem. We make a conservative alternative compilation of the measured SFR data over the redshift range 0 ≤z ≤ 7. We show that by only including published SFR data for which the dust obscuration has been directly determined, the ratio of the observed massive SFR to the observed supernova rate R{sub SN} has large uncertainties ∼1.8{sub −0.6}{sup +1.6} and is statistically consistent with no supernova rate problem. If we further consider that a significant fraction of massive stars will end their lives as faint ONeMg SNe or as failed SNe leading to a black hole remnant, then the ratio reduces to ∼1.1{sub −0.4}{sup +1.0} and the rate problem is essentially solved. We next examine the prospects for detecting this solution to the supernova rate problem. We first study the sources of uncertainty involved in the theoretical estimates of the neutrino detection rate and analyze whether the spectrum of relic neutrinos can be used to independently identify the existence of a supernova rate problem and its source. We consider an ensemble of published and unpublished core collapse supernova simulation models to estimate the uncertainties in the anticipated neutrino luminosities and temperatures. We illustrate how the spectrum of detector events might be used to establish the average

  3. Supernovae in the First Two Years of the Dark Energy Survey

    NASA Astrophysics Data System (ADS)

    D'Andrea, Christopher; Dark Energy Survey

    2016-01-01

    The Dark Energy Survey Supernova Program (DES-SN) is a five year, 30 square degree cadenced search for type Ia supernovae (SNe Ia) using the Dark Energy Camera on the 4m Blanco Telescope. The goal of DES-SN is to accurately measure more than 3000 SNe Ia over a redshift range of 0.1 < z < 1.2 to derive the most precise constraints for cosmological parameters of any supernova survey. I will present an overview of the data from the full first two seasons of DES-SN and a preliminary analysis using both spectroscopically- and photometrically-classified SNe Ia.

  4. Radio Observations of SN 2006jc

    NASA Astrophysics Data System (ADS)

    Soderberg, Alicia

    2006-10-01

    "I observed the Type Ib SN 2006jc (CBET 666) with the Very Large Array on Oct 14.7 and Oct 15.7 UT as part of an ongoing program to study the radio properties of Type Ibc supernovae. SN 2006jc is not detected at 4.9, 8.5 or 22.5 GHz. At a distance of 24 Mpc, the radio luminosity of SN 2006jc is at least a factor of 100 lower than that of SN 1998bw at a similar epoch (Kulkarni et al., 1998, Nature, 395, 663).

  5. Optical observations of the type Ic supernova 2007gr in NGC 1058

    SciTech Connect

    Chen, Juncheng; Wang, Xiaofeng; Li, Junzheng; Ganeshalingam, Mohan; Silverman, Jeffrey M.; Filippenko, Alexei V.; Li, Weidong; Chornock, Ryan; Steele, Thea E-mail: wang_xf@mail.tsinghua.edu.cn

    2014-08-01

    We present extensive optical observations of the normal Type Ic supernova (SN) 2007gr, spanning from about one week before maximum light to more than one year thereafter. The optical light and color curves of SN 2007gr are very similar to those of the broad-lined Type Ic SN 2002ap, but the spectra show remarkable differences. The optical spectra of SN 2007gr are characterized by unusually narrow lines, prominent carbon lines, and slow evolution of the line velocity after maximum light. The earliest spectrum (taken at t = –8 days) shows a possible signature of helium (He I λ5876 at a velocity of ∼19,000 km s{sup –1}). Moreover, the larger intensity ratio of the [O I] λ6300 and λ6364 lines inferred from the early nebular spectra implies a lower opacity of the ejecta shortly after the explosion. These results indicate that SN 2007gr perhaps underwent a less energetic explosion of a smaller-mass Wolf-Rayet star (∼8-9 M{sub ☉}) in a binary system, as favored by an analysis of the progenitor environment through pre-explosion and post-explosion Hubble Space Telescope images. In the nebular spectra, asymmetric double-peaked profiles can be seen in the [O I] λ6300 and Mg I] λ4571 lines. We suggest that the two peaks are contributed by the blueshifted and rest-frame components. The similarity in velocity structure and the different evolution of the strength of the two components favor an aspherical explosion with the ejecta distributed in a torus or disk-like geometry, but inside the ejecta the O and Mg have different distributions.

  6. Supernova Forensics

    NASA Astrophysics Data System (ADS)

    Soderberg, Alicia M.

    2014-01-01

    For decades, the study of stellar explosions -- supernovae -- have focused almost exclusively on the strong optical emission that dominates the bolometric luminosity in the days following the ultimate demise of the star. Yet many of the leading breakthroughs in our understanding of stellar death have been enabled by obtaining data at other wavelengths. For example, I have shown that 1% of all supernovae give rise to powerful relativistic jets, representing the biggest bangs in the Universe since the Big Bang. My recent serendipitous X-ray discovery of a supernova in the act of exploding (“in flagrante delicto”) revealed a novel technique to discover new events and provide clues on the shock physics at the heart of the explosion. With the advent of sensitive new radio telescopes, my research group combines clues from across the electromagnetic spectrum (radio to gamma-ray), leading us to a holistic study of stellar death, the physics of the explosions, and their role in fertilizing the Universe with new elements, by providing the community with cosmic autopsy reports.

  7. Early Results from the DES SN Survey

    NASA Astrophysics Data System (ADS)

    Scolnic, Daniel; Dark Energy Survey

    2016-01-01

    The Dark Energy Survey Supernova program (DES SN) has already discovered over 1000 Type Ia supernovae with well-sampled multi-color light curves in the redshift range 0.1 < z < 1.2. I will present an overview of the survey and show recent advances in our detection, photometry, calibration and spectroscopic follow-up pipelines. I will go over initial results from photometric classification of our sample and discuss methods used to reach measurements of cosmological parameters.

  8. Reverse and forward shock X-ray emission in an evolutionary model of supernova remnants undergoing efficient diffusive shock acceleration

    SciTech Connect

    Lee, Shiu-Hang; Patnaude, Daniel J.; Slane, Patrick O.; Ellison, Donald C.; Nagataki, Shigehiro E-mail: shiu-hang.lee@riken.jp E-mail: slane@cfa.harvard.edu E-mail: don_ellison@ncsu.edu

    2014-08-20

    We present new models for the forward and reverse shock thermal X-ray emission from core-collapse and Type Ia supernova remnants (SNRs) that include the efficient production of cosmic rays (CR) via nonlinear diffusive shock acceleration (DSA). Our CR-hydro-NEI code takes into account non-equilibrium ionization, hydrodynamic effects of efficient CR production on the SNR evolution, and collisional temperature equilibration among heavy ions and electrons in both the shocked supernova (SN) ejecta and the shocked circumstellar material. While X-ray emission is emphasized here, our code self-consistently determines both thermal and non-thermal broadband emission from radio to TeV energies. We include Doppler broadening of the spectral lines by thermal motions of the ions and by the remnant expansion. We study, in general terms, the roles that the ambient environment, progenitor models, temperature equilibration, and processes related to DSA have on the thermal and non-thermal spectra. The study of X-ray line emission from young SNRs is a powerful tool for determining specific SN elemental contributions and for providing critical information that helps to understand the type and energetics of the explosion, the composition of the ambient medium in which the SN exploded, and the ionization and dynamics of the hot plasma in the shocked SN ejecta and interstellar medium. With the approaching launch of the next-generation X-ray satellite Astro-H, observations of spectral lines with unprecedented high resolution will become a reality. Our self-consistent calculations of the X-ray spectra from various progenitors will help interpret future observations of SNRs.

  9. Photometric selection of Type Ia supernovae in the Supernova Legacy Survey

    NASA Astrophysics Data System (ADS)

    Bazin, G.; Ruhlmann-Kleider, V.; Palanque-Delabrouille, N.; Rich, J.; Aubourg, E.; Astier, P.; Balland, C.; Basa, S.; Carlberg, R. G.; Conley, A.; Fouchez, D.; Guy, J.; Hardin, D.; Hook, I. M.; Howell, D. A.; Pain, R.; Perrett, K.; Pritchet, C. J.; Regnault, N.; Sullivan, M.; Fourmanoit, N.; González-Gaitán, S.; Lidman, C.; Perlmutter, S.; Ripoche, P.; Walker, E. S.

    2011-10-01

    We present a sample of 485 photometrically identified Type Ia supernova candidates mined from the first three years of data of the CFHT SuperNova Legacy Survey (SNLS). The images were submitted to a deferred processing independent of the SNLS real-time detection pipeline. Light curves of all transient events were reconstructed in the gM, rM, iM and zM filters and submitted to automated sequential cuts in order to identify possible supernovae. Pure noise and long-term variable events were rejected by light curve shape criteria. Type Ia supernova identification relied on event characteristics fitted to their light curves assuming the events to be normal SNe Ia. The light curve fitter SALT2 was used for this purpose, assigning host galaxy photometric redshifts to the tested events. The selected sample of 485 candidates is one magnitude deeper than that allowed by the SNLS spectroscopic identification. The contamination by supernovae of other types is estimated to be 4%. Testing Hubble diagram residuals with this enlarged sample allows us to measure the Malmquist bias due to spectroscopic selections directly. The result is fully consistent with the precise Monte Carlo based estimate used to correct SN Ia distance moduli in the SNLS 3-year cosmological analyses. This paper demonstrates the feasibility of a photometric selection of high redshift supernovae with known host galaxy redshifts, opening interesting prospects for cosmological analyses from future large photometric SN Ia surveys.

  10. Tycho Brahe's Supernova: Light from Centuries Past

    NASA Astrophysics Data System (ADS)

    Ruiz-Lapuente, Pilar

    2004-09-01

    The light curve of SN 1572 is described in the terms used nowadays to characterize Type Ia supernovae (SNe Ia). By assembling the records of the observations done in 1572-1574 and evaluating their uncertainties, it is possible to recover the light curve and the color evolution of this supernova. It is found that within the SN Ia family, the event should have been an SN Ia with a normal rate of decline, its stretch factor being s~0.9. The visual light curve near maximum, late-time decline, and color evolution sustain this conclusion. After correcting for extinction, the luminosity of this supernova as observed at maximum is found to be MV=-19.24-5log(D/3.0kpc)+/-0.42. From stretch fitting of the overall light curve, the maximum in V would imply a luminosity difference of +0.17+/-0.1 mag, with the maximum brightness of an s=1 SN Ia. The quantity MV is consistent with a distance of 2.8+/-0.4 kpc for the scale of H0=65 km s-1 Mpc-1.

  11. Classifying supernovae using only galaxy data

    SciTech Connect

    Foley, Ryan J.; Mandel, Kaisey

    2013-12-01

    We present a new method for probabilistically classifying supernovae (SNe) without using SN spectral or photometric data. Unlike all previous studies to classify SNe without spectra, this technique does not use any SN photometry. Instead, the method relies on host-galaxy data. We build upon the well-known correlations between SN classes and host-galaxy properties, specifically that core-collapse SNe rarely occur in red, luminous, or early-type galaxies. Using the nearly spectroscopically complete Lick Observatory Supernova Search sample of SNe, we determine SN fractions as a function of host-galaxy properties. Using these data as inputs, we construct a Bayesian method for determining the probability that an SN is of a particular class. This method improves a common classification figure of merit by a factor of >2, comparable to the best light-curve classification techniques. Of the galaxy properties examined, morphology provides the most discriminating information. We further validate this method using SN samples from the Sloan Digital Sky Survey and the Palomar Transient Factory. We demonstrate that this method has wide-ranging applications, including separating different subclasses of SNe and determining the probability that an SN is of a particular class before photometry or even spectra can. Since this method uses completely independent data from light-curve techniques, there is potential to further improve the overall purity and completeness of SN samples and to test systematic biases of the light-curve techniques. Further enhancements to the host-galaxy method, including additional host-galaxy properties, combination with light-curve methods, and hybrid methods, should further improve the quality of SN samples from past, current, and future transient surveys.

  12. CONDITIONS FOR SUPERNOVAE-DRIVEN GALACTIC WINDS

    SciTech Connect

    Nath, Biman B.; Shchekinov, Yuri E-mail: yus@sfedu.ru

    2013-11-01

    We point out that the commonly assumed condition for galactic outflows, that supernovae (SNe) heating is efficient in the central regions of starburst galaxies, suffers from invalid assumptions. We show that a large filling factor of hot (≥10{sup 6} K) gas is difficult to achieve through SNe heating, irrespective of the SN's initial gas temperature and density, its uniformity, or its clumpiness. We instead suggest that correlated supernovae from OB associations in molecular clouds in the central region can drive powerful outflows if the molecular surface density is >10{sup 3} M {sub ☉} pc{sup –2}.

  13. Electron-capture supernovae exploding within their progenitor wind

    NASA Astrophysics Data System (ADS)

    Moriya, Takashi J.; Tominaga, Nozomu; Langer, Norbert; Nomoto, Ken'ichi; Blinnikov, Sergei I.; Sorokina, Elena I.

    2014-09-01

    The most massive stars on the asymptotic giant branch (AGB), or the so-called super-AGB stars, are thought to produce supernovae triggered by electron captures in their degenerate O+Ne+Mg cores. Super-AGB stars are expected to have slow winds with high mass-loss rates, so their circumstellar density is high. The explosions of super-AGB stars are therefore presumed to occur in this dense circumstellar environment. We provide the first synthetic light curves for such events by exploding realistic electron-capture supernova progenitors within their super-AGB winds. We find that the early light curve - that is, before the recombination wave reaches the bottom of the hydrogen-rich envelope of supernova ejecta (the plateau phase) - is not affected by the dense wind. However, after the luminosity drop following the plateau phase, the luminosity remains much higher when the super-AGB wind is taken into account. We compare our results to the historical light curve of SN 1054, the progenitor of the Crab Nebula, and show that the explosion of an electron-capture supernova within an ordinary super-AGB wind can explain the observed light curve features. We conclude that SN 1054 could have been a Type IIn supernova without any extra extreme mass loss, which was previously suggested to be necessary to account for its early high luminosity. We also show that our light curves match Type IIn supernovae with an early plateau phase or the so-called Type IIn-P supernovae, and suggest that they are electron-capture supernovae within super-AGB winds. Although some electron-capture supernovae can be bright in the optical spectral range due to the large progenitor radius, their X-ray luminosity from the interaction does not necessarily get as bright as other Type IIn supernovae whose optical luminosities are also powered by the interaction. Thus, we suggest that optically bright X-ray-faint Type IIn supernovae can emerge from electron-capture supernovae. Optically faint Type IIn supernovae

  14. IUE investigations of SN 1987A

    NASA Technical Reports Server (NTRS)

    Kirshner, Robert P.

    1989-01-01

    IUE observations of the SN 1987A began shortly after the discovery and have been frequent through 1988 and 1989, using the fine error sensor for photometry, low dispersion spectra for the supernova spectrum, and high dispersion observations for the interstellar medium when the supernova was bright and for circumstellar gas surrounding the supernova as the initial event faded. The UV data were very useful in determining which star exploded, assessing the ionizing pulse produced as the shock hit the surface of the star, and in constraining the stellar evolution that preceded the explosion through observations of a circumstellar shell.

  15. HOST GALAXY PROPERTIES AND HUBBLE RESIDUALS OF TYPE Ia SUPERNOVAE FROM THE NEARBY SUPERNOVA FACTORY

    SciTech Connect

    Childress, M.; Aldering, G.; Aragon, C.; Bailey, S.; Fakhouri, H. K.; Hsiao, E. Y.; Kim, A. G.; Loken, S.; Antilogus, P.; Bongard, S.; Canto, A.; Cellier-Holzem, F.; Guy, J.; Baltay, C.; Buton, C.; Kerschhaggl, M.; Kowalski, M.; Chotard, N.; Copin, Y.; Gangler, E. [Universite de Lyon, F-69622, Lyon; Universite de Lyon 1, Villeurbanne; CNRS and others

    2013-06-20

    We examine the relationship between Type Ia supernova (SN Ia) Hubble residuals and the properties of their host galaxies using a sample of 115 SNe Ia from the Nearby Supernova Factory. We use host galaxy stellar masses and specific star formation rates fitted from photometry for all hosts, as well as gas-phase metallicities for a subset of 69 star-forming (non-active galactic nucleus) hosts, to show that the SN Ia Hubble residuals correlate with each of these host properties. With these data we find new evidence for a correlation between SN Ia intrinsic color and host metallicity. When we combine our data with those of other published SN Ia surveys, we find the difference between mean SN Ia brightnesses in low- and high-mass hosts is 0.077 {+-} 0.014 mag. When viewed in narrow (0.2 dex) bins of host stellar mass, the data reveal apparent plateaus of Hubble residuals at high and low host masses with a rapid transition over a short mass range (9.8 {<=} log (M{sub *}/M{sub Sun }) {<=} 10.4). Although metallicity has been a favored interpretation for the origin of the Hubble residual trend with host mass, we illustrate how dust in star-forming galaxies and mean SN Ia progenitor age both evolve along the galaxy mass sequence, thereby presenting equally viable explanations for some or all of the observed SN Ia host bias.

  16. The evolution of supernova remnants in different galactic environments, and its effects on supernova statistics

    NASA Technical Reports Server (NTRS)

    Kafatos, M.; Sofia, S.; Bruhweiler, F.; Gull, T. R.

    1980-01-01

    Examination of the interaction between supernova (SN) ejecta and the various environments in which the explosive event might occur shows that only a small fraction of the many SNs produce observable supernova remnants (SNRs). This fraction, which is found to depend weakly upon the lower mass limit of the SN progenitors, and more strongly on the specfic characteristics of the associated interstellar medium, decreases from approximately 15 percent near the galctic center to 10 percent at Rgal approximately 10 kpc and drops nearly to zero for Rgal 15 kpc. Generally, whether a SNR is detectable is determined by the density of the ambient interstellar medium in which it is embeeede. The presence of large, low density cavities arpund stellar associations due to the combined effects of stellar winds and supernova shells strongly suggests that a large portion of the detectable SNRs have runway stars as their progenitors. These results explain the differences between the substantially larger SN rates in the galaxy derived both from pulsar statistics and from observations of SN events in external galaxies, when compared to the substantially smaller SN rates derived form galactic SNR statistics.

  17. Three Gravitationally Lensed Supernovae Behind Clash Galaxy Clusters

    NASA Technical Reports Server (NTRS)

    Patel, Brandon; McCully, Curtis; Jha, Saurbh W.; Rodney, Steven A.; Jones, David O.; Graur, Or; Merten, Julian; Zitrin, Adi; Riess, Adam G.; Matheson, Thomas; Sako, Masao; Holoien, Thomas W. -S.; Postman, Marc; Coe, Dan; Bartelmann, Matthias; Balestra, Italo; Benitez, Narciso; Bouwens, Rychard; Bradley, Larry; Broadhurst, Tom; Cenko, Stephen Bradley; Donahue, Megan; Filippenko, Alexei V.; Ford, Holland; Garnavich, Peter; Grillo, Claudio; Infante, Leopoldo; Jouvel, Stephanie; Kelson, Daniel; Koekemoer, Anton; Lahav, Ofer; Lemze, Doron; Maoz, Dan; Medezinski, Elinor; Melchior, Peter; Meneghetti, Massimo; Molino, Alberto; Moustakas, John; Moustakas, Leonidas A.; Nonino, Mario; Rosati, Piero; Seitz, Stella; Strolger, Louis G.; Umetsu, Keiichi; Zheng, Wei

    2014-01-01

    We report observations of three gravitationally lensed supernovae (SNe) in the Cluster Lensing And Supernova survey with Hubble (CLASH) Multi-Cycle Treasury program. These objects, SN CLO12Car (z = 1.28), SN CLN12Did (z = 0.85), and SN CLA11Tib (z = 1.14), are located behind three different clusters, MACSJ1720.2+3536 (z = 0.391), RXJ1532.9+3021 (z = 0.345), and A383 (z = 0.187), respectively. Each SN was detected in Hubble Space Telescope optical and infrared images. Based on photometric classification, we find that SNe CLO12Car and CLN12Did are likely to be Type Ia supernovae (SNe Ia), while the classification of SN CLA11Tib is inconclusive. Using multi-color light-curve fits to determine a standardized SN Ia luminosity distance, we infer that SN CLO12Car was approx. 1.0 +/- 0.2 mag brighter than field SNe Ia at a similar redshift and ascribe this to gravitational lens magnification. Similarly, SN CLN12Did is approx. 0.2 +/- 0.2 mag brighter than field SNe Ia. We derive independent estimates of the predicted magnification from CLASH strong+weak-lensing maps of the clusters (in magnitude units, 2.5 log10 µ): 0.83 +/- 0.16 mag for SN CLO12Car, 0.28 +/- 0.08 mag for SN CLN12Did, and 0.43 +/- 0.11 mag for SN CLA11Tib. The two SNe Ia provide a new test of the cluster lens model predictions: we find that the magnifications based on the SN Ia brightness and those predicted by the lens maps are consistent. Our results herald the promise of future observations of samples of cluster-lensed SNe Ia (from the ground or space) to help illuminate the dark-matter distribution in clusters of galaxies, through the direct determination of absolute magnifications.

  18. Supernova Optical Observations and Theory

    NASA Astrophysics Data System (ADS)

    Maeda, Keiichi; Bersten, Melina C.; Moriya, Takashi J.; Folatelli, Gaston; Nomoto, Ken'ichi

    2014-01-01

    We review emission processes within the supernova (SN) ejecta. Examples of the application of the theory to observational data are presented. The emission processes and thermal condition within the SN ejecta change as a function of time, and multi-epoch observations are important to obtain comprehensive views. Through the analyses, we can constrain the progenitor radius, compositions as a function of depth, ejecta properties, explosion asymmetry and so on. Multi-frequency follow-up is also important, including radio synchrotron emissions and the inverse Compton effect, γ-ray emissions from radioactive decay of newly synthesized materials. The optical data are essential to make the best use of the multi-frequency data.

  19. Progenitors of type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Maeda, Keiichi; Terada, Yukikatsu

    2016-07-01

    Natures of progenitors of type Ia Supernovae (SNe Ia) have not yet been clarified. There has been long and intensive discussion on whether the so-called single degenerate (SD) scenario or the double degenerate (DD) scenario, or anything else, could explain a major population of SNe Ia, but the conclusion has not yet been reached. With rapidly increasing observational data and new theoretical ideas, the field of studying the SN Ia progenitors has been quickly developing, and various new insights have been obtained in recent years. This paper aims at providing a summary of the current situation regarding the SN Ia progenitors, both in theory and observations. It seems difficult to explain the emerging diversity seen in observations of SNe Ia by a single population, and we emphasize that it is important to clarify links between different progenitor scenarios and different sub-classes of SNe Ia.

  20. SPECTRA AND LIGHT CURVES OF FAILED SUPERNOVAE

    SciTech Connect

    Fryer, Chris L.; Dahl, Jon A.; Fontes, Christopher J. E-mail: dahl@lanl.go

    2009-12-10

    Astronomers have proposed a number of mechanisms to produce supernova explosions. Although many of these mechanisms are now not considered primary engines behind supernovae (SNe), they do produce transients that will be observed by upcoming ground-based surveys and NASA satellites. Here, we present the first radiation-hydrodynamics calculations of the spectra and light curves from three of these 'failed' SNe: SNe with considerable fallback, accretion-induced collapse of white dwarfs, and energetic helium flashes (also known as type Ia SNe).

  1. Powerful Nearby Supernova Caught By Web

    NASA Astrophysics Data System (ADS)

    2008-09-01

    One of the nearest supernovas in the last 25 years has been identified over a decade after it exploded. This result was made possible by combining data from the vast online archives from many of the world's premier telescopes. The supernova was first singled out in 2001 by Franz Bauer, then at Penn State and now at Columbia University, who noticed a bright, variable object in the spiral galaxy Circinus using NASA's Chandra X-ray Observatory. Though the source displayed some exceptional properties, at the time Bauer and his Penn State colleagues could not confidently identify its nature. It was not until years later that Bauer and his team were able to confirm this object was a supernova. Clues in a spectrum from the European Southern Observatory's Very Large Telescope (VLT) led the team to search through data from 18 different telescopes, both in space and on the ground, nearly all of which was from archives. Because this object was found in a nearby galaxy, making it relatively easy to study, the public archives of these telescopes contained abundant data on this galaxy. The data show that this supernova, dubbed SN 1996cr, is among the brightest supernovas ever seen in radio and X-rays. It also bears many striking similarities to the famous supernova SN 1987A, which occurred in a galaxy only 160,000 light years from Earth. "This supernova appears to be a wild cousin of SN 1987A," said Bauer. "These two look alike in many ways, except this newer supernova is intrinsically a thousand times brighter in radio and X-rays." Optical images from the archives of the Anglo-Australian Telescope in Australia show that SN 1996cr exploded between February 28, 1995 and March 15, 1996, nearly a decade after SN 1987A. SN 1996cr may not have been noticed by astronomers at the time because it was only visible in the southern hemisphere, which is not as widely monitored as the northern. Among the five nearest supernovas of the last 25 years, it is the only one that was not seen

  2. Discovery of a Supernova in HST imaging of the MACSJ0717 Frontier Field

    NASA Astrophysics Data System (ADS)

    Rodney, Steven A.; Lotz, Jennifer; Strolger, Louis-Gregory

    2013-10-01

    We report the discovery of a supernova (SN) in Hubble Space Telescope (HST) observations centered on the galaxy cluster MACSJ0717. It was discovered in the F814W (i) band of the Advanced Camera for Surveys (ACS), in observations that were collected as part of the ongoing HST Frontier Fields (HFF) program (PI:J.Lotz, HST PID 13498). The FrontierSN ID for this object is SN HFF13Zar (nicknamed "SN Zara").

  3. Light Curve Models for Type IA Supernovae

    NASA Astrophysics Data System (ADS)

    Dominguez, Inmaculada

    1993-05-01

    The most widely accepted scenario for Type Ia supernovae is the thermonuclear explosion of a C+O white dwarf which, by accretion from a companion, approaches the Chandrasekhar mass. Whilst this scenario can account for most of the observed properties of SNe Ia, the exact nature of the explosion mechanism remains uncertain. This thesis presents the results obtained from hydrodynamical model calculations of post-explosion envelope expansion. The hydrodynamics are followed in spherical symmetry using a Lagrangean code, the energy equation being solved in the diffusion approximation. The conversion of decay gamma-rays into thermal energy is treated as an absorption process, while the time-dependent opacity is calculated as a function of composition, density, temperature and velocity gradient. The results of these models--light-curve shape, maximum luminosities, and expansion velocity profiles---are compared with the bolometric observational data (SN1981B, SN1972E and the composite light curve obtained by Leibundgut for 9 SNe Ia in Virgo) and current theoretical models of the explosion mechanism. Delayed detonation and deflagration models (Bravo 1990), adopting different C ignition densities, have been investigated. In all cases, the resulting light curve is in satisfactory agreement with observations. As the ignition density varies, the maximum of light remains nearly constant and the dispersion in the rates of decline of the light curve is compatible with observations. Moreover, variation in the ignition density readily accounts for the dispersion of 1000 km s^-1 in the observed expansion velocities. Delayed detonation models yield high kinetic energies, that result in (especially for the highest ignition densities) high expansion velocities, steep post-peak declines of the light curves and velocity distribution of intermediate-mass elements that are higher than that inferred from observations. Conversely, deflagration models provide less energetic explosions. However

  4. Dust and Other Recent Discoveries in SN 1987A

    NASA Technical Reports Server (NTRS)

    Sonneborn, George

    2011-01-01

    Supernova 1987 A in the Large Magellanic Cloud is one of the most intensively studied objects in the universe and a Rosetta Stone for understanding the explosions of massive stars. Now almost 25 years old, SN 1987 A is a very young supernova remnant, a phase previously unobserved in any other supernova. In this talk I will discuss recent observations from the far ultraviolet to the far-infrared with HST, the VLT, and the Herschel Space Observatory. These data reveal new insights into the composition, geometry, and heating of the explosion debris, the shock interaction with circumstellar material, and dust in the SN 1987 A system.

  5. SN 2014J and the Harvard Observing Project

    NASA Astrophysics Data System (ADS)

    McIntosh, Melissa; Bieryla, Allyson; Newton, Elisabeth R.; Lewis, John A.; Vanderburg, Andrew; Alexander, Kate Denham; Blanchard, Peter

    2014-06-01

    A chance discovery on January 21, 2014 by Steve Fossey et al. of University College London during an undergraduate telescope training session revealed the closest type Ia supernova in the past 42 years. The bright SN 2014J was observed by undergraduates and graduate students alike in the Harvard Observing Project (see poster by A. Bieryla) with the Clay Telescope at Harvard University. Observations were obtained in multiple filters starting January 24, 2014, prior to the supernova reaching its peak brightness, and monitoring will continue as the supernova fades in brightness. We will present multiple band light curve photometry and color RGB images of SN 2014J and its host galaxy M82.

  6. STELLAR BINARY COMPANIONS TO SUPERNOVA PROGENITORS

    SciTech Connect

    Kochanek, Christopher S.

    2009-12-20

    For typical models of binary statistics, 50%-80% of core-collapse supernova (ccSN) progenitors are members of a stellar binary at the time of the explosion. Independent of any consequences of mass transfer, this has observational consequences that can be used to study the binary properties of massive stars. In particular, the secondary companion to the progenitor of a Type Ib/c SN is frequently (approx50%) the more optically luminous star since the high effective temperatures of the stripped progenitors make it relatively easy for a lower luminosity, cooler secondary to emit more optical light. Secondaries to the lower mass progenitors of Type II SN will frequently produce excess blue emission relative to the spectral energy distribution of the red primary. Available data constrain the models weakly. Any detected secondaries also provide an independent lower bound on the progenitor mass and, for historical SN, show that it was not a Type Ia event. Bright ccSN secondaries have an unambiguous, post-explosion observational signature-strong, blueshifted, relatively broad absorption lines created by the developing SN remnant (SNR). These can be used to locate historical SN with bright secondaries, confirm that a source is a secondary, and, potentially, measure abundances of ccSN ejecta. Luminous, hot secondaries will re-ionize the SNR on timescales of 100-1000 yr that are faster than re-ionization by the reverse shock, creating peculiar H II regions due to the high metallicity and velocities of the ejecta.

  7. Dark Matter Ignition of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Bramante, Joseph

    2015-10-01

    Recent studies of low redshift type Ia supernovae (SN Ia) indicate that half explode from less than Chandrasekhar mass white dwarfs, implying ignition must proceed from something besides the canonical criticality of Chandrasekhar mass SN Ia progenitors. We show that 1-100 PeV mass asymmetric dark matter, with imminently detectable nucleon scattering interactions, can accumulate to the point of self-gravitation in a white dwarf and collapse, shedding gravitational potential energy by scattering off nuclei, thereby heating the white dwarf and igniting the flame front that precedes SN Ia. We combine data on SN Ia masses with data on the ages of SN Ia-adjacent stars. This combination reveals a 2.8 σ inverse correlation between SN Ia masses and ignition ages, which could result from increased capture of dark matter in 1.4 vs 1.1 solar mass white dwarfs. Future studies of SN Ia in galactic centers will provide additional tests of dark-matter-induced type Ia ignition. Remarkably, both bosonic and fermionic SN Ia-igniting dark matter also resolve the missing pulsar problem by forming black holes in ≳10 Myr old pulsars at the center of the Milky Way.

  8. Dark Matter Ignition of Type Ia Supernovae.

    PubMed

    Bramante, Joseph

    2015-10-01

    Recent studies of low redshift type Ia supernovae (SN Ia) indicate that half explode from less than Chandrasekhar mass white dwarfs, implying ignition must proceed from something besides the canonical criticality of Chandrasekhar mass SN Ia progenitors. We show that 1-100 PeV mass asymmetric dark matter, with imminently detectable nucleon scattering interactions, can accumulate to the point of self-gravitation in a white dwarf and collapse, shedding gravitational potential energy by scattering off nuclei, thereby heating the white dwarf and igniting the flame front that precedes SN Ia. We combine data on SN Ia masses with data on the ages of SN Ia-adjacent stars. This combination reveals a 2.8σ inverse correlation between SN Ia masses and ignition ages, which could result from increased capture of dark matter in 1.4 vs 1.1 solar mass white dwarfs. Future studies of SN Ia in galactic centers will provide additional tests of dark-matter-induced type Ia ignition. Remarkably, both bosonic and fermionic SN Ia-igniting dark matter also resolve the missing pulsar problem by forming black holes in ≳10  Myr old pulsars at the center of the Milky Way. PMID:26551803

  9. IT'S ALIVE{exclamation_point} THE SUPERNOVA IMPOSTOR 1961V

    SciTech Connect

    Van Dyk, Schuyler D.; Matheson, Thomas

    2012-02-20

    Reports of the death of the precursor of supernova (SN) 1961V in NGC 1058 are exaggerated. Consideration of the best astrometric data shows that the star, known as 'Object 7', lies at the greatest proximity to SN 1961V and is the likely survivor of the 'SN impostor' super-outburst. SN 1961V does not coincide with a neighboring radio source and is therefore not a radio SN. Additionally, the current properties of Object 7, based on data obtained with the Hubble Space Telescope, are consistent with it being a quiescent luminous blue variable (LBV). Furthermore, post-explosion non-detections by the Spitzer Space Telescope do not necessarily and sufficiently rule out a surviving LBV. We therefore consider, based on the available evidence, that it is still a bit premature to reclassify SN 1961V as a bona fide SN. The inevitable demise of this star, though, may not be too far off.

  10. Pair production of helicity-flipped neutrinos in supernovae

    SciTech Connect

    Perez, A.; Gandhi, R.

    1989-07-03

    We calculate the emissivity for the pair production of helicity-flipped neutrinos, in a way that can be used in supernova calculations. We also present some simple estimates which show that such processes can act as an efficient energy-loss mechanism in the shocked supernova core, and we use this fact to extract neutrino mass limits from SN1987A neutrino observations. 24 refs., 2 figs.

  11. An unusually fast-evolving supernova.

    PubMed

    Poznanski, Dovi; Chornock, Ryan; Nugent, Peter E; Bloom, Joshua S; Filippenko, Alexei V; Ganeshalingam, Mohan; Leonard, Douglas C; Li, Weidong; Thomas, Rollin C

    2010-01-01

    Analyses of supernovae (SNe) have revealed two main types of progenitors: exploding white dwarfs and collapsing massive stars. Here we describe SN 2002bj, which stands out as different from any SN reported to date. Its light curve rose and declined very rapidly, yet reached a peak intrinsic brightness greater than -18 magnitude. A spectrum obtained 7 days after discovery shows the presence of helium and intermediate-mass elements, yet no clear hydrogen or iron-peak elements. The spectrum only barely resembles that of a type Ia SN, with added carbon and helium. Its properties suggest that SN 2002bj may be representative of a class of progenitors that previously has been only hypothesized: a helium detonation on a white dwarf, ejecting a small envelope of material. New surveys should find many such objects, despite their scarcity. PMID:19892941

  12. First supernova companion star found

    NASA Astrophysics Data System (ADS)

    2004-01-01

    Supernova 1993J exploding hi-res Size hi-res: 222 kb Credits: ESA and Justyn R. Maund (University of Cambridge) Supernova 1993J exploding (artist’s impression) New observations with the Hubble Space Telescope allow a look into a supernova explosion under development. In this artist’s view the red supergiant supernova progenitor star (left) is exploding after having transferred about 10 solar masses of hydrogen gas to the blue companion star (right). This interaction process happened over about 250 years and affected the supernova explosion to such an extent that SN 1993J was later known as one of the most peculiar supernovae ever seen. Supernova 1993J exploding hi-res Size hi-res: 4200 kb Credits: ESA and Justyn R. Maund (University of Cambridge) The site of the Supernova 1993J explosion A virtual journey into one of the spiral arms of the grand spiral Messier 81 (imaged with the Isaac Newton Telescope on La Palma, left) reveals the superb razor-sharp imaging power of the NASA/ESA Hubble Space Telescope (Hubble’s WFPC2 instrument, below). The close-up (with Hubble’s ACS, to the right) is centred on the newly discovered companion star to Supernova 1993J that itself is no longer visible. The quarter-circle around the supernova companion is a so-called light echo originating from sheets of dust in the galaxy reflecting light from the original supernova explosion. Supernova 1993J explosing site hi-res Size hi-res: 1502 kb Credits: ESA and Justyn R. Maund (University of Cambridge) Close-up of the Supernova 1993J explosion site (ACS/HRC image) This NASA/ESA Hubble Space Telescope image shows the area in Messier 81 where Supernova 1993J exploded. The companion to the supernova ‘mother star’ that remains after the explosion is seen in the centre of the image. The image is taken with Hubble’s Advanced Camera for Surveys and is a combination of four exposures taken with ACS’ High Resolution Camera. The exposures were taken through two near-UV filters (250W

  13. Direct Measurement of the Supernova Rate in Starburst Galaxies

    NASA Technical Reports Server (NTRS)

    Bregman, Jesse D.; Temi, Pasquale; Rank, David; DeVincenzi, Donald L. (Technical Monitor)

    1999-01-01

    Supernovae play a key role in the dynamics, structure, and chemical evolution of galaxies. The massive stars that end their lives as supernovae live for short times. Many are still associated with dusty star formation regions when they explode, making them difficult to observe at visible wavelengths. In active star forming regions (galactic nuclei and starburst regions), dust extintion is especially severe. Thus, determining the supernova rate in the active star forming regions of galaxies, where the supernova rate can be one or two orders of magnitude higher than the average, has proven to be difficult. From observations of SN1987A, we know that the [NiII] 6.63 micron emission line was the strongest line in the infrared spectrum for a period of a year and a half after the explosion. Since dust extintion is much less at 6.63 pm than at visible wavelengths (A(sub 6.63)/A(sub V) = 0.025), the NiII line can be used as a sensitive probe for the detection of recent supernovae. We have observed a sample of starburst galaxies at 6.63 micron using ISOCAM to search for the NiII emission line characteristic of recent supernovae. We did not detect any NiII line emission brighter than a 5sigma limit of 5 mJy. We can set upper limits to the supernova rate in our sample, scaled to the rate in M82, of less than 0.3 per year at the 90% confidence level using Bayesian methods. Assuming that a supernova would have a NiII with the same luminosity as observed in SN1987A, we find less than 0.09 and 0.15 per year at the 50% and 67% confidence levels. These rates are somewhat less if a more normal type II supernovae has a NiII line luminosity greater than the line in SN1987A.

  14. Long gamma-ray Bursts and Type Ic Core CollapseSupernovae have Similar Environments

    SciTech Connect

    Kelly, P.L.; Kirshner, R.P.; Pahre, M.

    2007-12-04

    When the afterglow fades at the site of a long-duration {gamma}-ray burst (LGRB), Type Ic supernovae (SN Ic) are the only type of core collapse supernova observed. Recent work found that a sample of LGRB had different environments from a collection of core-collapse supernovae identified in a high-redshift sample from colors and light curves. LGRB were in the brightest regions of their hosts, but the core-collapse sample followed the overall distribution of the galaxy light. Here we examine 263 fully spectroscopically-typed supernovae found in nearby (z < 0.06) galaxies for which we have constructed surface photometry from the Sloan Digital Sky Survey (SDSS). The distributions of the thermonuclear supernovae (SN Ia) and some varieties of core-collapse supernovae (SN II and SN Ib) follow the galaxy light, but the SN Ic (like LGRB) are much more likely to erupt in the brightest regions of their hosts. The high-redshift hosts of LGRB are overwhelmingly irregulars, without bulges, while many low redshift SN Ic hosts are spirals with small bulges. When we remove the bulge light from our low-redshift sample, the SN Ic and LGRB distributions agree extremely well. If both LGRB and SN Ic stem from very massive stars, then it seems plausible that the conditions necessary for forming SN Ic are also required for LGRB. Additional factors, including metallicity, may determine whether the stellar evolution of a massive star leads to a LGRB with an underlying broad-lined SN Ic, or simply a SN Ic without a {gamma}-ray burst.

  15. Supernova Spectroscopy with the Southern African Large Telescope

    NASA Astrophysics Data System (ADS)

    Pandya, Viraj; Jha, S.; McCully, C.; Patel, B.; Camacho, Y.

    2014-01-01

    Supernova (SN) spectroscopy is important not only for classification and redshifts, but it also allows us to probe explosion mechanisms and progenitors. Here we report on optical spectroscopy of recent SNe using the Southern African Large Telescope (SALT) with the Robert Stobie Spectrograph (RSS). We have developed an automated data reduction pipeline for our longslit SN observations, paying particular attention to combining multiple exposures with different wavelength settings spanning the optical range. Furthermore, we investigate and implement an automated method for removing telluric features in the spectra. Finally, we present results exploring spectrum synthesis to model our growing database of type Ia supernovae.

  16. Gamma Ray Burst with a delayed Supernovae explosion

    NASA Astrophysics Data System (ADS)

    Fargion, Daniele

    2016-07-01

    The Gamma Ray Burst models didn't find yet an explanation of a few percent well known GRB-SN events. The puzzle is based on the difficulties to make twice an explosion in the same place by a single collapsing star.The possible presence of a persistent and precessing jet from a neutron star or a Black hole whose blazing to us is observed as a GRB cannot naturally explain the additional late Supernova explosion. We Show that there is a new simple and well based astrophysical configuration able to make both the GRB and the late Supernova-like explosion, solving the main puzzle of GRB-SN signature.

  17. X-ray Observations of the Tycho Supernova Remnant

    NASA Astrophysics Data System (ADS)

    Hughes, John P.

    2006-06-01

    In this presentation I summarize some key new findings from recent Chandra and XMM-Newton data on the remnant of the supernova (SN) observed by Tycho Brahe in 1572, which is widely believed to have been of Type Ia origin. Studies of the Tycho supernova remnant (SNR) at the current epoch address aspects of SN Ia physics, the evolution of young SNRs, and cosmic ray acceleration at high Mach-number shocks.Research on the Tycho SNR at Rutgers has been supported by Chandra grants GO3-4066X and AR5-6010X.

  18. Are 44Ti-producing supernovae exceptional?

    NASA Astrophysics Data System (ADS)

    The, L.-S.; Clayton, D. D.; Diehl, R.; Hartmann, D. H.; Iyudin, A. F.; Leising, M. D.; Meyer, B. S.; Motizuki, Y.; Schönfelder, V.

    2006-05-01

    According to standard models supernovae produce radioactive 44Ti, which should be visible in gamma-rays following decay to 44Ca for a few centuries. 44Ti production is believed to be the source of cosmic 44Ca, whose abundance is well established. Yet, gamma-ray telescopes have not seen the expected young remnants of core collapse events. The 44Ti mean life of τ ≃ 89 y and the Galactic supernova rate of ≃3/100 y imply ≃several detectable 44Ti gamma-ray sources, but only one is clearly seen, the 340-year-old Cas A SNR. Furthermore, supernovae which produce much 44Ti are expected to occur primarily in the inner part of the Galaxy, where young massive stars are most abundant. Because the Galaxy is transparent to gamma-rays, this should be the dominant location of expected gamma-ray sources. Yet the Cas A SNR as the only one source is located far from the inner Galaxy (at longitude 112°). We evaluate the surprising absence of detectable supernovae from the past three centuries. We discuss whether our understanding of SN explosions, their 44Ti yields, their spatial distributions, and statistical arguments can be stretched so that this apparent disagreement may be accommodated within reasonable expectations, or if we have to revise some or all of the above aspects to bring expectations in agreement with the observations. We conclude that either core collapse supernovae have been improbably rare in the Galaxy during the past few centuries, or 44Ti-producing supernovae are atypical supernovae. We also present a new argument based on 44Ca/40Ca ratios in mainstream SiC stardust grains that may cast doubt on massive-He-cap type I supernovae as the source of most galactic 44Ca.

  19. Energetic composites

    DOEpatents

    Danen, Wayne C.; Martin, Joe A.

    1993-01-01

    A method for providing chemical energy and energetic compositions of matter consisting of thin layers of substances which will exothermically react with one another. The layers of reactive substances are separated by thin layers of a buffer material which prevents the reactions from taking place until the desired time. The reactions are triggered by an external agent, such as mechanical stress or an electric spark. The compositions are known as metastable interstitial composites (MICs). This class of compositions includes materials which have not previously been capable of use as energetic materials. The speed and products of the reactions can be varied to suit the application.

  20. Energetic composites

    DOEpatents

    Danen, W.C.; Martin, J.A.

    1993-11-30

    A method for providing chemical energy and energetic compositions of matter consisting of thin layers of substances which will exothermically react with one another. The layers of reactive substances are separated by thin layers of a buffer material which prevents the reactions from taking place until the desired time. The reactions are triggered by an external agent, such as mechanical stress or an electric spark. The compositions are known as metastable interstitial composites (MICs). This class of compositions includes materials which have not previously been capable of use as energetic materials. The speed and products of the reactions can be varied to suit the application. 3 figures.

  1. SN1987A's Twentieth Anniversary

    NASA Astrophysics Data System (ADS)

    2007-02-01

    Looking back at 20 Years of Observations of this Supernova with ESO telescopes The unique supernova SN 1987A has been a bonanza for astrophysicists. It provided several observational 'firsts,' like the detection of neutrinos from an exploding star, the observation of the progenitor star on archival photographic plates, the signatures of a non-spherical explosion, the direct observation of the radioactive elements produced during the blast, observation of the formation of dust in the supernova, as well as the detection of circumstellar and interstellar material. ESO PR Photo 08a/07 ESO PR Photo 08a/07 SN1987A in the Large Magellanic Cloud Today, it is exactly twenty years since the explosion of Supernova 1987A in the Large Magellanic Cloud was first observed, at a distance of 163,000 light-years. It was the first naked-eye supernova to be seen for 383 years. Few events in modern astronomy have met with such an enthusiastic response by the scientists and now, after 20 years, it continues to be an extremely exciting object that is further studied by astronomers around the world, in particular using ESO's telescopes. When the first signs of Supernova 1987A, the first supernova of the year 1987, were noticed early on 24 February of that year, it was clear that this would be an unusual event. It was discovered by naked-eye and on a panoramic photographic plate taken with a 10-inch astrograph on Las Campanas in Chile by Oscar Duhalde and Ian Shelton, respectively. A few hours earlier, still on 23 February, two large underground detectors - in Japan and the USA - had registered the passage of high-energy neutrinos. Since SN 1987A exploded in the Large Magellanic Cloud (LMC), it was only accessible to telescopes in the Southern Hemisphere, more particularly in Australia, South Africa, and South America. In Chile, ESO's observatory at La Silla with its armada of telescopes with sizes between 0.5 and 3.6-m, played an important role. ESO PR Photo 08c/07 ESO PR Photo 08c/07 The

  2. Gamma ray lines from buried supernovae

    NASA Technical Reports Server (NTRS)

    Morfill, G. E.; Meyer, P.

    1982-01-01

    An investigation is conducted concerning the possibility that supernovae (SN), located in dense interstellar clouds, might become the sources of gamma ray lines. The SN progenitor, in such a case, has to be an O or B star so that its evolutionary lifetime is short, and an explosion inside the cloud is still possible. It is shown that, in principle, a measurement of the abundances in the ejecta is possible. Attention is given to the characteristics of a model, the expected luminosity of gamma-ray lines, and the study of specific numerical examples for testing the feasibility of the considered mechanism. On the basis of the obtained results, it is concluded that gamma-ray line production by collisional excitation in confined supernovae remnants may be quite important.

  3. Properties of unusually luminous supernovae

    NASA Astrophysics Data System (ADS)

    Pan, Tony Shih Arng

    This thesis is a theoretical study of the progenitors, event rates, and observational properties of unusually luminous supernova (SN), and aims to identify promising directions for future observations. In Chapter 2, we present model light curves and spectra of pair-instability supernovae (PISNe) over a range of progenitor masses and envelope structures for Pop III stars. We calculate the rates and detectability of PISNe, core-collapse supernovae (CCSNe), and Type Ia SNe at the Epoch of Reionization with the James Webb Space Telescope (JWST), which can be used to determine the contribution of Pop III versus Pop II stars toward ionizing the universe. Although CCSNe are the least intrinsically luminous supernovae, Chapter 5 shows that a JWST survey targeting known galaxy clusters with Einstein radii > 35" should discover gravitationally lensed CCSNe at redshifts exceeding z = 7--8. In Chapter 3, we explain the Pop II/I progenitors of observed PISNe in the local universe can be created via mergers in runaway collisions in young, dense star clusters, despite copious mass loss via line-driven winds. The PISN rate from this mechanism is consistent with the observed volumetric rate, and the Large Synoptic Survey Telescope could discover ~102 such PISNe per year. In Chapter 4, we identify 10 star clusters which may host PISN progenitors with masses up to 600 solar masses formed via runaway collisions. We estimate the probabilities of these very massive stars being in eclipsing binaries to be ≳ 30%, and find that their transits can be detected even under the contamination of the background cluster light, due to mean transit depths of ~10 6 solar luminosities. In Chapter 6, we show that there could be X-ray analogues of optically super-luminous SNe that are powered by the conversion of the kinetic energy of SN ejecta into radiation upon its collision with a dense but optically-thin circumstellar shell. We find shell configurations that can convert a large fraction of the SN

  4. Survey for the Binary Progenitor in SN1006 and Update on SN1572

    NASA Astrophysics Data System (ADS)

    Ruiz-Lapuente, Pilar; Hernández, Jonay González; Tabernero, Hugo; Montes, David; Canal, Ramon; Mendez, Javier; Bedin, Luigi

    2013-01-01

    We have completed a survey down to R = 15 mag of the stars within a circle of 4 arcmin radius around the nominal center of the remnant of SN 1006, one of the three historical Type Ia supernovae (the other two being SN 1572 and SN 1604), in search of a possible surviving binary companion of the white dwarf whose explosion gave rise to the supernova. The stellar parameters (effective temperature, surface gravity, and metallicity), as well as the radial velocities of all the stars, have been measured from spectra obtained with the UVES spectrograph at the VLT, and from the former and the available photometry, distances have been determined. Chemical abundances of the Fe-peak elements Cr, Mn, Co, and Ni have also been measured to check for possible contamination of the stellar surface by the supernova ejecta. The limiting magnitude of the survey would allow us to find stellar companions of the red-giant type, subgiant stars, and main-sequence stars down to F5-6. Unlike in SN 1572, where a subgiant of type G0-1 has been proposed as the companion of SN 1572, for SN 1006 we can discard the possibility that SN 1006 had a red giant or subgiant companion.

  5. Models for supernova progenitors in massive binary systems

    NASA Astrophysics Data System (ADS)

    Yoon, Sung Chul

    2014-09-01

    The diversity of core-collapse supernovae is closely related to binary interactions. For example, the majority of Type Ib/c and Type IIb supernovae may occur in massive binary systems as a result of mass transfer at various evolutionary stages. I will present some evolutionary models of massive binary stars including several important physical ingredients, like tidal interactions and mass and angular momentum exchange, and discuss their implications for supernova progenitors and their populations. I will particularly emphasize that Type Ib/c supernova progenitors at their pre-supernova stage should have very different properties compared to the observed Wolf-Rayet stars, which are widely believed to represent SN Ibc progenitors, and that many observed properties of SNe Ib/c and IIb can be explained well with the binary scenario.

  6. ASASSN-16ke: Discovery of A Probable Supernova in AGC 331536

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Shields, J.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Bock, G.; Cruz, I.; Marples, P.; Post, R. S.

    2016-09-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy AGC 331536.

  7. ASASSN-16hz: Discovery of A Probable Supernova in 2MASX J23154564-0120135

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Post, R. S.; Kiyota, S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Cruz, I.; Stone, G.

    2016-08-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J23154564-0120135.

  8. ASASSN-16jw: Discovery of A Probable Supernova in IC 1780

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Brown, J. S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Shields, J.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Bock, G.; Cruz, I.; Kiyota, S.; Marples, P.; Masi, G.; Nicholls, B.; Post, R. S.; Stone, G.

    2016-09-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy IC 1780.

  9. ASASSN-16io: Discovery of A Probable Supernova in 2MASX J18400114+5413042

    NASA Astrophysics Data System (ADS)

    Nicolas, J.; Kiyota, S.; Cruz, I.; Stone, G.; Post, R. S.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Shields, J.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Brimacombe, J.

    2016-08-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J18400114+5413042.

  10. ASASSN-16if: Discovery of A Possible Supernova in AM 0557-522 NED03

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Cruz, I.; Kiyota, S.; Post, R. S.; Stone, G.

    2016-08-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, possibly a supernova, in the galaxy AM 0557-522 NED03.

  11. ASASSN-16cm: Discovery of A Probable Supernova in 2MASX J15192684-0055256

    NASA Astrophysics Data System (ADS)

    Brown, J. S.; Monard, L. A. G.; Dong, Subo; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Chen, Ping; Brimacombe, J.; Bock, G.; Conseil, E.; Fernandez, J. M.; Kiyota, S.; Masi, G.; Wiethoff, W.

    2016-03-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J15192684-0055256.

  12. ASASSN-16el: Discovery of A Probable Supernova in UGC 04671

    NASA Astrophysics Data System (ADS)

    Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.

    2016-04-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy UGC 04671.

  13. ASASSN-16ft: Discovery of A Probable Supernova in CGCG 382-005

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Bock, G.; Fernandez, J. M.; Kiyota, S.; Masi, G.; Nicholls, B.; Wiethoff, W.

    2016-06-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy CGCG 382-005.

  14. ASASSN-16cn: Discovery of A Probable Supernova in ESO 579-G018

    NASA Astrophysics Data System (ADS)

    Monard, L. A. G.; Cruz, I.; Brown, J. S.; Dong, Subo; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Chen, Ping; Brimacombe, J.; Bock, G.; Conseil, E.; Fernandez, J. M.; Kiyota, S.; Masi, G.; Wiethoff, W.

    2016-03-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy ESO 579-G018.

  15. ASASSN-16bv and ASASSN-16bw: Discovery of Two Probable Supernovae

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Kiyota, S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Cruz, I.; Masi, G.; Nicholls, B.

    2016-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy LCRS B014209.4-420839.

  16. ASASSN-16ej: Discovery of A Probable Supernova in UGC 11409

    NASA Astrophysics Data System (ADS)

    Kiyota, S.; Koff, R. A.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.; Bock, G.; Conseil, E.; Fernandez, J. M.; Masi, G.

    2016-04-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy UGC 11409.

  17. ASASSN-16fg and ASASSN-16fh: Discovery of Two Probable Supernovae

    NASA Astrophysics Data System (ADS)

    Monard, L. A. G.; Brimacombe, J.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Kiyota, S.; Koff, R. A.

    2016-05-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered two new transient sources, most likely a supernovae, in the galaxies 2MASX J00051603-1629348 and 2MASXi J0002057-265846.

  18. ASASSN-16hc: Discovery of A Probable Supernova in 2MASX J13590394+3308172

    NASA Astrophysics Data System (ADS)

    Masi, G.; Brown, J. S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.; Bock, G.; Kiyota, S.; Post, R. S.; Stone, G.

    2016-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J13590394+3308172.

  19. ASASSN-16cy: Discovery of A Probable Supernova in CGCG 295-010

    NASA Astrophysics Data System (ADS)

    Masi, G.; Fernandez, J. M.; Brimacombe, J.; Brown, J. S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Cruz, I.; Monard, L. A. G.

    2016-03-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy CGCG 295-010.

  20. ASASSN-16db: Discovery of A Probable Supernova in UGC 06198

    NASA Astrophysics Data System (ADS)

    Kiyota, S.; Brimacombe, J.; Brown, J. S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Fernandez, J. M.; Masi, G.; Nicholls, B.

    2016-03-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy UGC 06198.

  1. ASASSN-16ci: Discovery of A Type Ia Supernova in NGC 1272

    NASA Astrophysics Data System (ADS)

    Chornock, Ryan; Katebi, Reza; Brown, J. S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.

    2016-03-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy NGC 1272.

  2. ASASSN-16eq: Discovery of A Probable Supernova in UGC 11898

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Brown, J. S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping

    2016-04-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy UGC 11898.

  3. ASASSN-16eu: Discovery of A Probable Supernova in NGC 2649

    NASA Astrophysics Data System (ADS)

    Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.

    2016-04-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy NGC 2649.

  4. ASASSN-16do: Discovery of A Probable Supernova in an Uncatalogued Galaxy

    NASA Astrophysics Data System (ADS)

    Nicholls, B.; Brown, J. S.; Stanek, K. Z.; Dong, Subo; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Chen, Ping; Brimacombe, J.; Kiyota, S.; Masi, G.

    2016-03-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in an uncatalogued galaxy.

  5. ASASSN-16gv: Discovery of A Probable Supernova in CGCG 503-021

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Post, R. S.; Stone, G.

    2016-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy CGCG 503-021.

  6. ASASSN-16fx: Discovery of A Probable Supernova in GALEXASC J020044.56-461644.0

    NASA Astrophysics Data System (ADS)

    Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.

    2016-06-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy GALEXASC J020044.56-461644.0.

  7. ASASSN-16gu: Discovery of A Probable Supernova in NGC 4725

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Dong, Subo; Kochanek, C. S.; Stanek, K. Z.; Brown, J. S.; Holoien, T. W.-S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Chen, Ping; Fernandez, J. M.; Koff, R. A.; Post, R. S.; Stone, G.; Wiethoff, W.

    2016-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy NGC 4725.

  8. ASASSN-16em: Discovery of A Supernova in GALEXASC J133213.24+844042.7

    NASA Astrophysics Data System (ADS)

    Cruz, I.; Brimacombe, J.; Prieto, J. L.; Brown, J. S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Bersier, D.; Dong, Subo; Chen, Ping; Conseil, E.; Kiyota, S.; Koff, R. A.; Masi, G.

    2016-04-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy GALEXASC J133213.24+844042.7.

  9. ASASSN-16fa: Discovery of A Probable Supernova in UGC 06434

    NASA Astrophysics Data System (ADS)

    Kiyota, S.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.; Nicholls, B.

    2016-05-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy UGC 06434.

  10. ASASSN-16dn: Discovery of A Probable Supernova in GALEXASC J104848.62-201544.1

    NASA Astrophysics Data System (ADS)

    Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.

    2016-03-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy GALEXASC J104848.62-201544.1.

  11. ASASSN-16ek: Discovery of A Probable Supernova in a Bright, Uncatalogued Spiral Galaxy

    NASA Astrophysics Data System (ADS)

    Cruz, I.; Brown, J. S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.; Bock, G.; Conseil, E.; Kiyota, S.; Koff, R. A.; Masi, G.

    2016-04-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy GALEXASC J072024.60+325058.8.

  12. ASASSN-16fp: Discovery of A Probable Supernova in UGC 11868

    NASA Astrophysics Data System (ADS)

    Holoien, T. W.-S.; Stanek, K. Z.; Brown, J. S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.

    2016-05-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy UGC 11868.

  13. ASASSN-16bq and ASASSN-16br: Discovery of Two Probable Supernovae

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Brown, J. S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Bock, G.; Cruz, I.; Kiyota, S.; Masi, G.

    2016-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered two new transient sources, most likely supernovae, in the galaxies IC 0986 and 2MASX J15453055-1309057.

  14. ASASSN-16dw: Discovery of A Probable Supernova in 2MASX J13300119-2758297

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Cruz, I.; Fernandez, J. M.; Kiyota, S.; Marples, P.

    2016-04-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J13300119-2758297.

  15. ASASSN-16fs: Discovery of A Probable Supernova in UGC 09523

    NASA Astrophysics Data System (ADS)

    Masi, G.; Fernandez, J. M.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.; Bock, G.; Kiyota, S.; Nicholls, B.; Wiethoff, W.

    2016-06-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy UGC 09523.

  16. ASASSN-16am: Discovery of A Probable Supernova in CGCG 328-018

    NASA Astrophysics Data System (ADS)

    Masi, G.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.; Bock, G.; Kiyota, S.

    2016-01-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy CGCG 328-018.

  17. ASASSN-16ar: Discovery of A Supernova in 2MASX J04283087-1739233

    NASA Astrophysics Data System (ADS)

    Masi, G.; Bersier, D.; Shappee, B. J.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Prieto, J. L.; Dong, Subo; Chen, Ping; Brimacombe, J.; Bock, G.; Kiyota, S.

    2016-01-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J04283087-1739233.

  18. ASASSN-16bb: Discovery of A Probable Supernova in SDSS J140557.36+435257.2

    NASA Astrophysics Data System (ADS)

    Kiyota, S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.; Koff, R. A.; Masi, G.

    2016-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy SDSS J140557.36+435257.2.

  19. ASASSN-16gz and ASASSN-16ha: Discovery of Two Probable Supernovae

    NASA Astrophysics Data System (ADS)

    Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.

    2016-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered two new transient sources, most likely supernovae, in the galaxies APMUKS(BJ) B043218.28-211910.3 and Fairall 0673.

  20. ASASSN-16gn: Discovery of A Probable Supernova in SDSS J120657.56+271806.0

    NASA Astrophysics Data System (ADS)

    Koff, R. A.; Post, R. S.; Stone, G.; Brimacombe, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Bock, G.; Fernandez, J. M.; Masi, G.; Nicholls, B.; Nicolas, J.; Wiethoff, W.

    2016-06-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy SDSS J120657.56+271806.0.

  1. ASASSN-16fj: Discovery of A Probable Supernova in IC 1289

    NASA Astrophysics Data System (ADS)

    Cruz, I.; Brimacombe, J.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Kiyota, S.; Koff, R. A.; Monard, L. A. G.

    2016-05-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy IC 1289.

  2. ASASSN-16hd: Discovery of A Probable Supernova in GALEXASC J015051.89+223348.8

    NASA Astrophysics Data System (ADS)

    Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.

    2016-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy GALEXASC J015051.89+223348.8.

  3. ASASSN-16dm: Discovery of A Probable Supernova in 2MASX J11372059-0454450

    NASA Astrophysics Data System (ADS)

    Kiyota, S.; Masi, G.; Brown, J. S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.

    2016-03-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J11372059-0454450.

  4. ASASSN-16cc: Discovery of A Probable Supernova in NGC 2101

    NASA Astrophysics Data System (ADS)

    Brown, J. S.; Bersier, D.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Dong, Subo; Chen, Ping; Brimacombe, J.; Bock, G.; Cruz, I.; Fernandez, J. M.; Kiyota, S.; Masi, G.

    2016-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy NGC 2101.

  5. ASASSN-16fl: Discovery of A Probable Supernova in 2MASX J10065350-1543022

    NASA Astrophysics Data System (ADS)

    Nicholls, B.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.; Cruz, I.; Kiyota, S.; Koff, R. A.

    2016-05-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J10065350-1543022.

  6. ASASSN-16hw: Discovery of A Probable Supernova in GALEXASC J215327.92-342420.8

    NASA Astrophysics Data System (ADS)

    Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Shields, J.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Brimacombe, J.

    2016-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy GALEXASC J215327.92-342420.8.

  7. ASASSN-16gm: Discovery of A Probable Supernova in GALEXASC J200348.67-601528.7

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Nicholls, B.; Post, R. S.; Stone, G.; Wiethoff, W.

    2016-06-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy GALEXASC J200348.67-601528.7.

  8. ASASSN-16bx: Discovery of A Probable Supernova in CGCG 280-023

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Cruz, I.; Kiyota, S.; Masi, G.; Nicholls, B.

    2016-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy CGCG 280-023.

  9. ASASSN-16hh: Discovery of A Probable Supernova in MCG +03-06-031

    NASA Astrophysics Data System (ADS)

    Nicolas, J.; Kiyota, S.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.; Masi, G.; Post, R. S.; Stone, G.

    2016-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy MCG +03-06-031.

  10. ASASSN-16eh: Discovery of A Probable Supernova in SDSS J154029.29+005437.4

    NASA Astrophysics Data System (ADS)

    Brown, J. S.; Dong, Subo; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Chen, Ping; Brimacombe, J.; Bock, G.; Conseil, E.; Fernandez, J. M.; Kiyota, S.; Nicholls, B.

    2016-04-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy SDSS J154029.29+005437.4.

  11. ASASSN-16ex: Discovery of A Probable Supernova in SDSS J171023.63+262350.3

    NASA Astrophysics Data System (ADS)

    Kiyota, S.; Brimacombe, J.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping

    2016-05-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy SDSS J171023.63+262350.3.

  12. ASASSN-16hn: Discovery of A Probable Supernova in GALEXASC J000403.88-344851.6

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Shields, J.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Kiyota, S.; Nicolas, J.; Post, R. S.; Stone, G.

    2016-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy GALEXASC J000403.88-344851.6.

  13. ASASSN-16bn: Discovery of A Probable Supernova in 2MASX J03103162+0416184

    NASA Astrophysics Data System (ADS)

    Masi, G.; Brimacombe, J.; Kiyota, S.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Bock, G.; Cruz, I.; Fernandez, J. M.

    2016-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J03103162+0416184.

  14. ASASSN-16ay: Discovery of A Probable Supernova in UGC 03738

    NASA Astrophysics Data System (ADS)

    Koff, R. A.; Brimacombe, J.; Kiyota, S.; Brown, J. S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Bock, G.; Masi, G.

    2016-01-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy UGC 03738.

  15. ASASSN-16aw: Discovery of A Probable Supernova in ESO 306-G016

    NASA Astrophysics Data System (ADS)

    Kiyota, S.; Brown, J. S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.; Bock, G.; Koff, R. A.; Masi, G.

    2016-01-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy ESO 306-G016.

  16. ASASSN-16bg: Discovery of A Probable Supernova in 2MASX J12592491+2744198

    NASA Astrophysics Data System (ADS)

    Brown, J. S.; Dong, Subo; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Chen, Ping; Brimacombe, J.; Fernandez, J. M.; Kiyota, S.

    2016-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J12592491+2744198.

  17. ASASSN-16ec: Discovery of A Probable Supernova in 2MASX J13031054-2159149

    NASA Astrophysics Data System (ADS)

    Bock, G.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.; Cruz, I.; Fernandez, J. M.; Kiyota, S.; Marples, P.; Nicholls, B.

    2016-04-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J13031054-2159149.

  18. ASASSN-16hr: Discovery of A Probable Supernova in 2MASX J22253147+3859010

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Brown, J. S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Shields, J.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Kiyota, S.; Nicholls, B.; Post, R. S.; Stone, G.

    2016-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J22253147+3859010.

  19. ASASSN-16ff: Discovery of A Probable Supernova in ESO 218-G008

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Kiyota, S.; Brown, J. S.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Koff, R. A.; Monard, L. A. G.

    2016-05-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy ESO 218-G008.

  20. ASASSN-16bc: Discovery of A Probable Supernova in 2MASX J12052488-2123572

    NASA Astrophysics Data System (ADS)

    Fernandez, J. M.; Kiyota, S.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.; Koff, R. A.; Masi, G.

    2016-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J12052488-2123572.